WO2024166861A1 - 光学ガラスおよび光学素子 - Google Patents

光学ガラスおよび光学素子 Download PDF

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WO2024166861A1
WO2024166861A1 PCT/JP2024/003702 JP2024003702W WO2024166861A1 WO 2024166861 A1 WO2024166861 A1 WO 2024166861A1 JP 2024003702 W JP2024003702 W JP 2024003702W WO 2024166861 A1 WO2024166861 A1 WO 2024166861A1
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content
order
glass
cation
cation ratio
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PCT/JP2024/003702
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English (en)
French (fr)
Japanese (ja)
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昂浩 庄司
智明 根岸
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Hoya株式会社
豪雅光電科技（威海）有限公司
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Priority to JP2024576325A priority Critical patent/JPWO2024166861A1/ja
Priority to CN202480011528.0A priority patent/CN120603793A/zh
Publication of WO2024166861A1 publication Critical patent/WO2024166861A1/ja

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/062—Glass compositions containing silica with less than 40% silica by weight
    • C03C3/064—Glass compositions containing silica with less than 40% silica by weight containing boron
    • C03C3/068—Glass compositions containing silica with less than 40% silica by weight containing boron containing rare earths
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements

Definitions

  • the present invention relates to optical glass and optical elements having desired optical properties.
  • Lenses with high refractive indices and anomalous partial dispersion in each Abbe region are widely used in applications such as car-mounted cameras, digital cameras such as single-lens reflex cameras, and information portable terminal devices such as smartphones.
  • glass with high chemical durability and mechanical properties is required to improve the yield rate during lens manufacturing.
  • processing glass into aspheric lenses processing can be difficult if the glass has a high glass transition temperature. Therefore, there is a demand for glass with a reduced glass transition temperature.
  • Patent Document 1 discloses optical glass that has a high refractive index and anomalous partial dispersion in the visible to near ultraviolet range.
  • Patent Document 2 discloses optical glass that has a high refractive index and high transmittance in the near infrared range.
  • neither Patent Document 1 nor Patent Document 2 pays any attention to improving mechanical properties.
  • the present invention has been made in consideration of these circumstances, and aims to provide optical glass and optical elements that have desired optical constants, are inhibited from decreasing in chemical durability and mechanical properties, and do not have a high glass transition temperature.
  • the gist of the present invention is as follows:
  • the content of B3 + is more than 0 cation% and 50.00 cation% or less;
  • the content of F ⁇ exceeds 0 anion %,
  • the glass transition temperature Tg is 625° C. or lower, Knoop hardness is 450 or more, ⁇ Pg,F is ⁇ 0.0025 or more,
  • the Abbe number ⁇ d is 37.5 or more,
  • the content of Si4 + is 30 cation% or less, The Li + content is 30 cation% or less, The Na + content is 30 cation% or less, The content of K + is 30 cation% or less, The content of Mg2 + is 25 cation % or less, The Ca2 + content is 25 cation% or less, The content of Sr2 + is 25 cation % or less, The content of Ba2 + is 25 cation% or less, The Zn2 + content is 25 cation% or less, The La3 + content is 50 cation% or less, The content of Y3 + is 50 cation % or less, The content of Gd3 + is 30 cation % or less, The content of Zr4 + is 15 cation% or less, The content of Ta5 + is 15 cation% or less, The content of Ti4 + is 15 cation % or less, The content of Nb5 + is 15 cation% or less, The content of W6 + is 15 c
  • a glass material for press molding comprising the optical glass described in any one of (1) to (7) above.
  • the present invention provides optical glass and optical elements that have desired optical constants, are prevented from decreasing chemical durability and mechanical properties, and have a low glass transition temperature.
  • the glass composition of the optical glass is expressed in cation %, unless otherwise specified.
  • Cation % is the molar percentage when the total content of all cationic components is taken as 100%.
  • the content and total content of glass components are based on cation %, unless otherwise specified, and "%" means “cation %".
  • the cation ratio refers to the proportion (ratio) of the content of cationic components to each other (including the total content of multiple types of cationic components) in the cation %.
  • anion % is the molar percentage when the total content of all anion components is 100%.
  • the valence of the cationic component (for example, the valence of B 3+ is +3, the valence of Si 4+ is +4, and the valence of La 3+ is +3) is a value determined by convention, and is similar to the notation of B 2 O 3 , SiO 2 , and La 2 O 3 when expressing glass components B, Si, and La on an oxide basis. Therefore, when analyzing the glass composition, it is not necessary to analyze the valence of the cationic component.
  • the valence of the anionic component (for example, the valence of O 2- is -2) is also a value determined by convention, and is similar to the notation of glass components on an oxide basis as described above, for example, B 2 O 3 , SiO 2 , and La 2 O 3. Therefore, when analyzing the glass composition, it is not necessary to analyze the valence of the anionic component.
  • the content of glass components can be quantified by known methods, such as inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), ion chromatography (IC), non-dispersive infrared spectrometry (ND-IR), etc.
  • ICP-AES inductively coupled plasma atomic emission spectrometry
  • ICP-MS inductively coupled plasma mass spectrometry
  • IC ion chromatography
  • ND-IR non-dispersive infrared spectrometry
  • chemical durability refers to excellent water resistance Da and water resistance Dw or both.
  • mechanical properties refer to excellent hardness of glass as evaluated by Knoop hardness Hk.
  • Knoop hardness Hk is an index showing the indentation hardness of glass. Note that the unit of Knoop hardness Hk is "MPa", but since it is customary to omit the unit of Knoop hardness Hk in the technical field to which this invention belongs, the unit of Knoop hardness Hk will also be omitted in this specification.
  • the thermal stability and stability upon reheating of glass both refer to the difficulty of crystal precipitation in glass. Thermal stability refers to the difficulty of crystal precipitation when molten glass solidifies, and stability upon reheating refers to the difficulty of crystal precipitation when solidified glass is reheated, such as during reheat pressing.
  • reduced or suppressed volatilization of glass components means that the loss of glass components due to volatilization of glass components during melting is small or suppressed. If the loss of glass components due to volatilization during melting is small, fluctuations in various properties including the refractive index are suppressed, and the occurrence of internal defects such as striae inside the glass is suppressed, making it possible to stabilize quality. Furthermore, since the loss of glass components is small, the product yield relative to the input raw materials can be directly increased. On the other hand, glass components that are likely to volatilize during melting are components that contribute to a decrease in dispersibility, an increase in anomalous partial dispersion, and a decrease in the glass transition temperature Tg. Therefore, by suppressing the volatilization of these components, it is possible to provide optical glass and optical elements that have the desired optical constants and a glass transition temperature Tg that is not high.
  • the refractive index refers to the refractive index nd at the helium d line (wavelength 587.56 nm).
  • optical glass of the present invention is described in detail below.
  • the optical glass according to this embodiment is The content of B3 + is more than 0 cation% and 50.00 cation% or less, The content of F ⁇ exceeds 0 anion %, The glass transition temperature Tg is 600° C. or lower, Knoop hardness is 450 or more, ⁇ Pg,F is ⁇ 0.0025 or more, The refractive index nd and the Abbe number vd satisfy the following formula. nd ⁇ 0.0081 ⁇ d+2.1181
  • the content of B3 + is more than 0% and not more than 50.00%.
  • the lower limit of the content of B3 + is preferably 5%, and more preferably 10%, 15%, 17%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, and 26% in this order.
  • the upper limit of the content of B3 + is preferably 45.00%, and more preferably 40.00%, 39.00%, 38.00%, 37.00%, 36.00%, 35.00%, 34.00%, 33.00%, 32.00%, 31.00%, 30.00%, and 29.00% in this order.
  • the lower limit of the B3 + content is preferably 5%, and more preferably 10%, 15%, 17%, 19%, 21%, 23%, 25%, 27%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, and 36% in that order.
  • the upper limit of the B3 + content is preferably 45.00%, and more preferably 44.00%, 43.00%, 42.50%, 42.00%, 41.50%, 41.00%, 40.50%, and 40.00% in that order.
  • B3 + is a glass network forming component.
  • the chemical durability can be improved.
  • the content of B3+ is too low, the thermal stability and mechanical properties of the glass may be reduced.
  • the content of B3 + is too high, the volatilization of glass components may increase, and the thermal stability and chemical durability of the glass may be reduced.
  • the optical glass according to this embodiment contains F - as an anion component, that is, the content of F - exceeds 0 anion %.
  • the lower limit of the content of F - is preferably 5 anion %, and more preferably 10 anion %, 15 anion %, 20 anion %, 25 anion %, 27 anion %, 29 anion %, 30 anion %, 31 anion %, 32 anion %, 33 anion %, 34 anion %, 35 anion %, 36 anion %, 37 anion %, 38 anion %, 39 anion %, 40 anion %, 41 anion %, 42 anion %, 43 anion %, and 44 anion % in this order.
  • the upper limit of the F ⁇ content is preferably 80 anion%, and more preferably 75 anion%, 70 anion%, 65 anion%, 63 anion%, 61 anion%, 60 anion%, 59 anion%, 58 anion%, 57 anion%, 56 anion%, 55 anion%, 54 anion%, 53 anion%, 52 anion%, 51 anion%, 50 anion%, 49 anion%, 48 anion%, and 47 anion% in that order.
  • the lower limit of the F- content is preferably 15 anion%, and more preferably 17 anion%, 19 anion%, 21 anion%, 23 anion%, 24 anion%, 25 anion%, 26 anion%, 27 anion%, 28 anion%, 29 anion%, 30 anion%, and 31 anion% in that order.
  • the upper limit of the F ⁇ content is preferably 80 anion%, and more preferably 75 anion%, 70 anion%, 65 anion%, 63 anion%, 61 anion%, 59 anion%, 57 anion%, 55 anion%, 53 anion%, 51 anion%, 49 anion%, 47 anion%, 45 anion%, 43 anion%, 41 anion%, 40 anion%, 39 anion%, 38 anion%, 37 anion%, 36 anion%, and 35 anion%, in that order.
  • an optical glass having a high refractive index for its low dispersion, high thermal stability, anomalous partial dispersion, a low glass transition temperature Tg, and suitable for precision press molding can be obtained.
  • the F- content is too small, the thermal stability of the glass may be reduced, and anomalous partial dispersion may not be obtained. If the F- content is too large, the volatilization of glass components may increase.
  • the glass transition temperature Tg is 625° C. or less.
  • the upper limit of the glass transition temperature Tg is preferably 620° C., and more preferably 610° C., 600° C., 590° C., 580° C., 570° C., 560° C., 550° C., 540° C., 530° C., 520° C., 510° C., 500° C., 490° C., and 480° C. in that order.
  • the lower limit of the glass transition temperature Tg is preferably 350° C., and more preferably 360° C., 370° C., 380° C., 390° C., 400° C., 410° C., 420° C., 430° C., 440° C., 450° C., 460° C., and 470° C. in that order.
  • the upper limit of the glass transition temperature Tg is preferably 625°C, and more preferably 620°C, 615°C, 610°C, 595°C, 590°C, 585°C, and 580°C in that order.
  • the lower limit of the glass transition temperature Tg is preferably 350°C, and more preferably 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, and 500°C in that order.
  • the yield during precision press molding can be improved.
  • the glass transition temperature Tg is too high, precision press molding may not be possible.
  • Components that relatively lower the glass transition temperature Tg include Li + , Na + , K + , F - , etc.
  • Components that relatively raise the glass transition temperature Tg include La 3+ , Zr 4+ , Nb 5+ , etc.
  • the glass transition temperature Tg can be controlled by appropriately adjusting the contents of these components.
  • Knoop hardness Hk> In the optical glass according to this embodiment, the Knoop hardness is at least 450.
  • the lower limit of the Knoop hardness Hk is preferably 460, and more preferably 470, 480, 490, 500, 510, and 520 in that order.
  • the lower limit of the Knoop hardness Hk is preferably 400, and more preferably 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, and 550 in that order.
  • Knoop hardness Hk is set within the above range.
  • the Knoop hardness Hk is usually 750, and preferably 600.
  • the Knoop hardness Hk can be increased by adjusting the contents of La 3+ , Gd 3+ , Y 3+ , Si 4+ , Zr 4+ and Al 3+ .
  • ⁇ Pg,F is -0.0025 or more.
  • the lower limit of ⁇ Pg,F is preferably -0.0020, and more preferably -0.0010, 0.0000, 0.0010, 0.0020, 0.0030, 0.0040, 0.0050, 0.0060, 0.0070, and 0.0080 in that order.
  • the upper limit of ⁇ Pg,F is not particularly limited, but is preferably 0.0500, and more preferably 0.0400, 0.0300, 0.0200, 0.0150, 0.0140, 0.0130, 0.0120, 0.0110, and 0.0100.
  • the upper limit of ⁇ Pg,F is not particularly limited, but is preferably 0.0500, and further preferably 0.0400, 0.0300, 0.0200, 0.0150, 0.0140, 0.0130, 0.0120, 0.0110, or 0.0100.
  • the lower limit of ⁇ Pg,F is preferably -0.0022, and further preferably -0.0020, -0.0018, -0.0016, -0.0014, -0.0012, -0.0010, -0.0008, -0.0006, -0.0004, -0.0002, or 0.0000, in that order.
  • ⁇ Pg,F is calculated based on the partial dispersion ratio Pg,F as follows:
  • the partial dispersion ratio Pg,F is calculated from the values of the linear refractive indices obtained using Schott's dispersion formula described later.
  • the normal line is expressed by the following formula.
  • the Abbe number vd is 37.5 or more.
  • the Abbe number vd can also be 40 to 75, 50 to 70, 55 to 67, 57 to 65, 58 to 64, 59 to 63, or 56 to 60.
  • the Abbe number ⁇ d is preferably 37.5 to 60, and can also be 40 to 58, 45 to 56, 47 to 54, 48 to 52, 49 to 51, or 55 to 59, 56 to 58.
  • the Abbe number vd can be adjusted to a desired value by appropriately adjusting the content of each glass component.
  • Components that relatively lower the Abbe number vd i.e., high dispersion components, are Nb5 + , Ti4 + , Zr4 + , W6 + , Bi3 + , Ta5 + , etc.
  • components that relatively increase the Abbe number vd i.e., low dispersion components, are F- , Si4 + , B3 + , Li + , Na + , K + , La3 + , Ba2 + , Ca2 + , Sr2 + , etc.
  • the Abbe number ⁇ d and partial dispersion ratios Pg and F are calculated as follows. That is, the refractive index at the 12 wavelengths shown in Table A is measured according to the Japanese Industrial Standards (JIS) JIS B 7071-1, Method for measuring the refractive index of optical glass - Part 1: Minimum deviation method. Next, the refractive index of each line obtained by measurement is applied to the shot dispersion formula defined in Annex B of the Japanese Industrial Standards (JIS) JIS B 7071-1, Method for measuring the refractive index of optical glass - Part 1: Minimum deviation method, and the constants of the shot dispersion formula are found by the least squares method. Then, the Abbe number ⁇ d and partial dispersion ratios Pg and F are calculated from the values of each linear refractive index obtained using the shot dispersion formula with the constants determined.
  • n2 a0 + a1 ⁇ 2 + a2 ⁇ -2 + a3 ⁇ -4 + a4 ⁇ -6 + a5 ⁇ -8
  • n is the refractive index
  • ⁇ is the wavelength ( ⁇ m)
  • a 0 , a 1 , a 2 , a 3 , a 4 , and a 5 are constants.
  • the refractive index nd and the Abbe number vd satisfy the following formula [1-1].
  • the refractive index nd and the Abbe number vd preferably satisfy the following formula [1-2], and more preferably satisfy the following formulas [1-3], [1-4], and [1-5] in that order.
  • the refractive index nd and the Abbe number vd satisfy the following formula [2-1].
  • the refractive index nd and the Abbe number vd more preferably satisfy the following formula [2-2], and further more preferably satisfy the following formulas [2-3], [2-4], and [2-5] in that order.
  • the lower limit of the total content of Si4 + and B3 + [Si4 + + B3 + ] is preferably 10%, more preferably 15%, 20%, 22%, 24%, 26%, 28%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, and 37% in this order.
  • the upper limit of the total content is preferably 70%, more preferably 65%, 60%, 58%, 56%, 54%, 52%, 50%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, 41%, and 40% in this order.
  • the lower limit of the total content [ Si4+ + B3 + ] is preferably 10%, and more preferably 15%, 20%, 22%, 24%, 26%, 28%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, and 43% in this order.
  • the upper limit of the total content is preferably 70%, and more preferably 65%, 60%, 59%, 58%, 57%, 56%, 55%, 54%, 53%, 52%, 51%, 50%, 49%, 48%, 47%, 46%, and 45% in this order.
  • the total content [ Si4+ +B3 + ] is preferable for the total content [ Si4+ +B3 + ] to be within the above range.
  • the lower limit of the total content of Li + , Na + , and K + [Li ++ Na ++ K + ] is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 5%, and 6% in this order.
  • the upper limit of the total content is preferably 50%, and more preferably 45%, 40%, 35%, 30%, 25%, 20%, 18%, 16%, 14%, 13%, 12%, 11%, 10%, and 9% in this order.
  • the total content may be 0%.
  • the lower limit of the total content [Li + Na + K + ] is preferably 0%, more preferably 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, and 0.6%, in that order.
  • the upper limit of the total content is preferably 50%, more preferably 45%, 40%, 35%, 30%, 25%, 20%, 18%, 16%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, and 2%, in that order.
  • the total content [Li + +Na + +K + ] is within the above range.
  • the lower limit of the total content of Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ] is preferably 0%, and more preferably 1%, 3%, 5%, 7%, 9%, 10%, 11%, 12%, and 13% in this order.
  • the upper limit of the total content is preferably 30%, and more preferably 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, and 16% in this order.
  • the total content may be 0%.
  • the lower limit of the total content [ Mg2 + + Ca2 + + Sr2 + + Ba2 + ] is preferably 3.5%, more preferably 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, and 4.5% in that order.
  • the upper limit of the total content is preferably 30%, more preferably 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, and 8% in that order.
  • the total content [Mg 2+ + Ca 2+ + Sr 2+ + Ba 2+ ] is too small, the volatilization of glass components increases, and the thermal stability and devitrification resistance of the glass may decrease. If the total content is too large, the high refractive index may be impaired, and the thermal stability of the glass may be impaired. From the viewpoint of obtaining an optical glass having desired optical constants, reduced volatilization of glass components, and high thermal stability of the glass, it is preferable to set the total content within the above range.
  • the upper limit of the total content of Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ and Zn 2+ [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ ] is preferably 50%, and more preferably 45%, 40%, 35%, 30%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, and 16% in this order.
  • the lower limit of the total content is preferably 0%, and more preferably 1%, 3%, 5%, 7%, 9%, 10%, 11%, 12%, and 13% in this order.
  • the total content may be 0%.
  • the upper limit of the total content [ Mg2 + + Ca2 + + Sr2 + + Ba2 + + Zn2 + ] is preferably 30%, more preferably 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, and 8% in this order.
  • the lower limit of the total content is preferably 3.5%, more preferably 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, and 4.5% in this order.
  • the total content [Mg 2+ + Ca 2+ + Sr 2+ + Ba 2+ + Zn 2+ ] is too high, the high refractive index may be impaired and the thermal stability of the glass may be impaired. If the total content is too low, the volatilization of the glass components may increase, and the thermal stability and devitrification resistance of the glass may be reduced. Therefore, the total content is preferably within the above range.
  • the lower limit of the total content of Li + , Na + , K + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ is preferably 0%, and more preferably 1%, 3%, 5%, 7%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, and 20% in this order.
  • the upper limit of the total content is preferably 50%, and more preferably 45%, 40%, 35%, 32%, 30%, 29%, 28%, 27%, 26%, 25%, 24%, and 23% in this order.
  • the total content may be 0%.
  • the lower limit of the total content [Li + Na + K + Mg2 ++ Ca2 ++ Sr2 ++Ba2 + ] is preferably 3.5%, and more preferably 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, and 4.5% in that order.
  • the upper limit of the total content is preferably 50%, and more preferably 45%, 40%, 35%, 32%, 30%, 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, and 6%, in that order.
  • the total content [Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ] is preferable for the total content [Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ] to be in the above range.
  • the lower limit of the total content of Li + , Na + , K + , Rb + , Cs + , Mg2+, Ca2 + , Sr2 + , and Ba2+ [Li + Na + K + Rb + Cs + Mg2 + Ca2 + Sr2 +Ba2 + ] is preferably 0%. More preferably, the total content exceeds 0%.
  • the lower limit of the total content is more preferably 1%, and more preferably 3%, 5%, 7%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, and 20% in this order.
  • the upper limit of the total content is preferably 40%, and more preferably 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32%, 31%, 30%, 29%, 28%, 27%, 26%, 25%, 24%, and 23% in that order.
  • the total content may be 0%.
  • the lower limit of the total content of Li + , Na + , K + , Rb + , Cs + , Mg2+ , Ca2 + , Sr2+ , and Ba2+ is preferably 3.5%, and more preferably 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, and 4.5% in that order.
  • the upper limit of the total content is preferably 40%, and more preferably 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32%, 31%, 30%, 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, and 8%, in that order.
  • the total content [Li + +Na + + K + +Rb + +Cs + Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ] is preferable for the total content [Li + +Na + + K + +Rb + +Cs + Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ] to be in the above range.
  • the lower limit of the total content of La3 + , Gd3 + , and Y3+ [ La3 ++ Gd3 ++Y3 + ] is preferably 0%. More preferably, the total content exceeds 0%.
  • the lower limit of the total content is more preferably 5%, and more preferably 10%, 15%, 20%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, and 38% in this order.
  • the upper limit of the total content is preferably 70%, and more preferably 60%, 55%, 50%, 48%, 46%, 45%, 44%, 43%, 42%, and 41% in this order.
  • the lower limit of the total content of La3 + , Gd3 + , and Y3 + [La3++ Gd3 ++Y3 + ] is preferably 27%, and more preferably 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, and 44% in this order.
  • the upper limit of the total content is preferably 60%, and more preferably 58%, 56%, 55%, 54%, 53%, 52%, 51%, 50%, 49%, and 48% in this order.
  • the total content [La 3+ + Gd 3+ + Y 3+ ] is too low, the desired optical constants may not be obtained. If the total content is too high, the thermal stability of the glass may decrease. From the viewpoint of obtaining an optical glass with a high refractive index nd, it is preferable that the total content is within the above range.
  • the lower limit of the total content of Ti4 + , Nb5+ , W6 + , and Bi3+ [ Ti4 ++ Nb5 ++ W6 ++Bi3 + ] is preferably 0%, more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6% in this order.
  • the upper limit of the total content is preferably 20%, more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in this order.
  • the total content may be less than 2.0%.
  • the total content of Ti4 + , Nb5+ , W6 + , and Bi3 + [ Ti4 ++ Nb5 ++ W6 ++Bi3 + ] is preferably more than 0%, with the lower limit being preferably 0.1%, and more preferably 0.1%, 0.5%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, and 2.0% in that order.
  • the upper limit of the total content is preferably 20%, and more preferably 18%, 16%, 14%, 12%, 10%, 8%, 6%, 5%, 4%, 3.5%, 3.0%, and 2.5% in that order.
  • the total content may be 0%. Also, from the viewpoint of maintaining a desired Abbe number vd and improving anomalous partial dispersion in the visible to near ultraviolet region, it is preferable that the total content [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ] is within the above range.
  • the upper limit of the total content of Zr4 + and Ta5+ [ Zr4 + +Ta5 + ] is preferably 20%, more preferably 15%, 10%, 5%, 4%, 3%, 2% and 1% in that order.
  • the lower limit of the total content is preferably 0%, more preferably 0.1%, 0.2% and 0.3% in that order.
  • the upper limit of the total content of Zr4 + and Ta5 + [ Zr4+ + Ta5 + ] is preferably 20%, more preferably 15%, 10%, 9%, 8%, 7%, 6%, 5%, and 4% in that order, and the lower limit of the total content is preferably 0%, more preferably 0.5%, 1.0%, 1.5%, 2.0%, and 2.5% in that order.
  • the total content [ Zr4 + + Ta5 + ] may be 0%. From the viewpoint of maintaining the thermal stability of the glass, the total content is preferably set to the above range. If the total content is too high, the thermal stability of the glass may decrease, and the raw material cost may increase.
  • the upper limit of the total content of Ti4 + , Nb5+ , Bi3 + , W6 + , Zr4 + , and Ta5+ is preferably 20%, more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order.
  • the lower limit of the total content is preferably 0%, more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6% in that order.
  • the upper limit of the total content of Ti4 + , Nb5 + , Bi3 + , W6 + , Zr4 + , and Ta5+ is preferably 20%, more preferably 18%, 16%, 14%, 12%, 10%, 9%, 8%, 7%, and 6% in that order.
  • the lower limit of the total content is preferably 0%, more preferably 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, and 4.0% in that order.
  • the total content [ Ti4 + + Nb5 + + Bi3 + + W6 + + Zr4 + + Ta5 + ] may be 0%. Also, from the viewpoint of maintaining a desired Abbe number vd and improving anomalous partial dispersion in the visible to near ultraviolet region, it is preferable that the total content is within the above range.
  • the lower limit of the cation ratio [ Si4 + /( Si4 ++ B3+ ) ] of the content of Si4 + to the total content of Si4+ and B3+ is preferably 0.020, and more preferably 0.05, 0.070, 0.09, 0.13, 0.15, 0.17, 0.19, 0.21, 0.22, 0.23, 0.24, and 0.25 in this order.
  • the upper limit of the cation ratio is preferably 0.80, and more preferably 0.70, 0.60, 0.50, 0.40, 0.35, 0.34, 0.33, and 0.32 in this order.
  • the lower limit of the cation ratio of the content of Si4 + to the total content of Si4 + and B3+ [Si4 + /( Si4 ++ B3+ )] is preferably 0.070, and more preferably 0.08, 0.09, 0.10, 0.11, and 0.12 in this order.
  • the upper limit of the cation ratio is preferably 0.80, and more preferably 0.70, 0.60, 0.50, 0.40, 0.35, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, and 0.20 in this order.
  • the cation ratio [Si 4+ /(Si 4+ +B 3+ )] is within the above range.
  • the upper limit of the cationic ratio [ B3+ / ( Si4 ++B3 + )] of the content of B3 + to the total content of Si4+ and B3+ is preferably 0.980, and more preferably 0.95, 0.91, 0.87, 0.85, 0.83, 0.81, 0.79, 0.78, 0.77, 0.76, 0.75 in this order.
  • the lower limit of the cationic ratio is preferably 0.20, and more preferably 0.30, 0.40, 0.50, 0.60, 0.65, 0.66, 0.67, 0.68 in this order.
  • the upper limit of the cation ratio of the content of B3 + to the total content of Si4 + and B3 + [B3 + /( Si4 ++ B3+ )] is preferably 0.98, and more preferably 0.97, 0.96, 0.95, 0.94, 0.93, 0.92, 0.91, 0.90, 0.89, and 0.88 in that order.
  • the lower limit of the cation ratio is preferably 0.20, and more preferably 0.30, 0.40, 0.50, 0.60, 0.65, 0.67, 0.69, 0.71, 0.73, 0.75, 0.77, 0.79, and 0.80 in that order.
  • the cation ratio [B 3+ /(Si 4+ +B 3+ )] is within the above range.
  • the lower limit of the total content of Si4 + , B3 + , and P5+ [ Si4 ++ B3 ++P5 + ] is preferably 10%, more preferably 15%, 20%, 22%, 24%, 26%, 28%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, and 37% in this order.
  • the upper limit of the total content is preferably 70%, more preferably 65%, 60%, 58%, 56%, 54%, 52%, 50%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, 41%, and 40% in this order.
  • the lower limit of the total content of Si4 + , B3 + , and P5+ [ Si4 ++ B3 ++P5 + ] is preferably 10%, and more preferably 15%, 20%, 22%, 24%, 26%, 28%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, and 43% in that order.
  • the upper limit of the total content is preferably 70%, and more preferably 65%, 60%, 58%, 56%, 54%, 52%, 50%, 48%, 47%, 46%, and 45% in that order.
  • the total content [ Si4+ + B3 + +P5 + ] is preferable for the total content [ Si4+ + B3 + +P5 + ] to be in the above-mentioned range.
  • the upper limit of the cation ratio [ Si4 + /(Si4++B3++P5+)] of the content of Si4 + to the total content of Si4 + , B3 + , and P5 + is preferably 0.80, more preferably 0.70, 0.60, 0.50, 0.40, 0.35, 0.34, 0.33, and 0.32 in this order.
  • the lower limit of the cation ratio is preferably 0.020, more preferably 0.05, 0.09, 0.13, 0.15, 0.17, 0.19, 0.21, 0.22, 0.23, 0.24, and 0.25 in this order.
  • the upper limit of the cation ratio [ Si4 + /(Si4++ B3 ++P5 + )] of the content of Si4 + to the total content of Si4 + , B3 + , and P5 + is preferably 0.80, and more preferably 0.70, 0.60, 0.50, 0.40, 0.35, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, and 0.20 in that order.
  • the lower limit of the cation ratio is preferably 0.070, and more preferably 0.08, 0.09, 0.10, 0.11, and 0.12 in that order.
  • the cation ratio [Si 4+ /(Si 4+ +B 3+ +P 5+ )] be in the above range.
  • the upper limit of the cationic ratio [B3 + /( Si4++B3++P5+)] of the content of B3+ to the total content of Si4+ , B3 + , and P5 + is preferably 0.980, and more preferably 0.95, 0.91, 0.87, 0.85, 0.83, 0.81, 0.79, 0.78, 0.77, 0.76, and 0.75 in this order.
  • the lower limit of the cationic ratio is preferably 0.20, and more preferably 0.30, 0.40, 0.50, 0.60, 0.65, 0.66, 0.67, and 0.68 in this order.
  • the upper limit of the cationic ratio [B3 + /(Si4++ B3 ++P5 + )] of the content of B3 + to the total content of Si4 + , B3 + , and P5 + is preferably 0.98, and more preferably 0.97, 0.96, 0.95, 0.94, 0.93, 0.92, 0.91, 0.90, 0.89, and 0.88 in that order.
  • the lower limit of the cationic ratio is preferably 0.20, and more preferably 0.30, 0.40, 0.50, 0.60, 0.65, 0.67, 0.69, 0.71, 0.73, 0.75, 0.77, 0.79, and 0.80 in that order.
  • the cation ratio [B 3+ /(Si 4+ +B 3+ +P 5+ )] is within the above range.
  • the upper limit of the cationic ratio [P5 + /( Si4 ++ B3 ++P5+)] of the content of P5+ to the total content of Si4 + , B3 + , and P5 + is preferably 0.50, and more preferably 0.40, 0.30, 0.20, 0.10, 0.08, 0.06, 0.04, and 0.02 in this order.
  • the lower limit of the cationic ratio is preferably 0, and more preferably 0.005, 0.01, and 0.015 in this order.
  • the cationic ratio may be 0.
  • the upper limit of the cationic ratio [P5 + /( Si4 ++ B3 ++P5 + )] of the content of P5+ to the total content of Si4 +, B3 + , and P5+ is preferably 0.50, and more preferably 0.40, 0.30, 0.20, 0.10, 0.08, 0.06, 0.04, and 0.02 in that order.
  • the lower limit of the cationic ratio is preferably 0, and more preferably 0.005, 0.01, and 0.015 in that order.
  • the cationic ratio may be 0.
  • the cation ratio [P 5+ /(Si 4+ +B 3+ +P 5+ )] is within the above range.
  • the upper limit of the cation ratio [Li + / (Li ++ Na ++ K + )] of the content of Li + to the total content of Li + , Na+, and K + is preferably 1, more preferably 0.95, 0.90, and 0.85 in that order.
  • the lower limit of the cation ratio is preferably 0, more preferably 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 in that order.
  • the cation ratio may be 1.
  • the upper limit of the cation ratio [Li + / (Li ++ Na ++ K + )] of the content of Li+ to the total content of Li + , Na+, and K+ is preferably 1, more preferably 0.95, 0.90, and 0.85 in that order.
  • the lower limit of the cation ratio is preferably 0, more preferably 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 in that order.
  • the cation ratio may be 1.
  • the cation ratio [Li + /(Li + +Na + +K + )] is within the above range.
  • the upper limit of the cationic ratio [Na + /(Li + +Na + +K + )] of the content of Na + to the total content of Li + , Na + , and K + is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, and 0.3 in this order.
  • the lower limit of the cationic ratio is preferably 0, and more preferably 0.05, 0.10, and 0.15 in this order.
  • the cationic ratio may be 0.
  • the upper limit of the cationic ratio [Na + /(Li + + Na + +K + )] of the content of Na + to the total content of Li + , Na + , and K + is preferably 1, and more preferably 0.9 , 0.8, 0.7, 0.6, 0.5, 0.4, and 0.3 in that order.
  • the lower limit of the cationic ratio is preferably 0, and more preferably 0.05, 0.10, and 0.15 in that order.
  • the cationic ratio may be 0.
  • the cation ratio [Na + /(Li + +Na + +K + )] is within the above range.
  • the upper limit of the cation ratio [K + /(Li + Na + K+)] of the content of K + to the total content of Li + , Na + , and K + is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, and 0.3 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, and 0.15 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [K + / (Li + Na + K + )] of the content of K + to the total content of Li + , Na+, and K + is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, and 0.3 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, and 0.15 in this order.
  • the cation ratio may be 0.
  • the cation ratio [K + /(Li + +Na + +K + )] is within the above range.
  • the upper limit of the cation ratio [ Mg2+ / (Mg2++ Ca2 ++ Sr2 ++Ba2 + )] of the content of Mg2 + to the total content of Mg2+, Ca2 + , Sr2 + , and Ba2+ is preferably 1, and more preferably 0.9, 0.8 , 0.7, 0.6, 0.55, 0.5, 0.45, and 0.4 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.18 , 0.2, 0.22, 0.24, 0.26, 0.28, and 0.3 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Mg2 + /( Mg2 ++ Ca2 ++ Sr2 ++Ba2 + )] of the content of Mg2 + to the total content of Mg2+, Ca2 +, Sr2 + , and Ba2+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.55, 0.5, 0.45, and 0.4 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28, and 0.3 in that order.
  • the cation ratio may be 0.
  • the cation ratio [Mg 2+ /(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ )] is preferably in the above range.
  • the upper limit of the cation ratio [Ca2 + /(Mg2++ Ca2 ++ Sr2 ++Ba2+)] of the content of Ca2 + to the total content of Mg2 + , Ca2 + , Sr2 + , and Ba2 + is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.1 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio of the content of Ca2 + to the total content of Mg2 + , Ca2 + , Sr2 + , and Ba2 + [Ca2 + /( Mg2 ++ Ca2 ++ Sr2 ++Ba2 + )] is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.1 in that order.
  • the cation ratio may be 0.
  • the cation ratio [Ca 2+ /(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ )] is preferably in the above range.
  • the upper limit of the cation ratio [Sr2 + /( Mg2 ++ Ca2 ++ Sr2 ++Ba2+)] of the content of Sr2 + to the total content of Mg2+, Ca2 + , Sr2 + , and Ba2 + is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.1 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cationic ratio of the content of Sr2 + to the total content of Mg2 + , Ca2 + , Sr2 + , and Ba2 + [Sr2 + /( Mg2 ++ Ca2 ++ Sr2 ++Ba2 + )] is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in that order.
  • the lower limit of the cationic ratio is preferably 0, and more preferably 0.05 and 0.1 in that order.
  • the cationic ratio may be 0.
  • the cation ratio [Sr 2+ /(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ )] is preferably in the above range.
  • the lower limit of the cation ratio [Ba2 + /( Mg2 ++ Ca2 ++Sr2 ++ Ba2 + )] of the content of Ba2+ to the total content of Mg2+, Ca2 + , Sr2 + , and Ba2 + is preferably 0, and more preferably 0.1, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, and 0.60 in this order.
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.90, 0.80, 0.75, 0.74, 0.73, 0.72, 0.71, and 0.70 in this order.
  • the lower limit of the cation ratio [Ba2 + /( Mg2 ++ Ca2 ++ Sr2 ++Ba2 + )] of the content of Ba2 + to the total content of Mg2 + , Ca2 + , Sr2 + , and Ba2+ is preferably 0, and more preferably 0.1, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, and 0.60 in this order.
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.90, 0.80, 0.75, 0.74, 0.73, 0.72, 0.71, and 0.70 in this order.
  • the cation ratio [Ba 2+ /(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ )] is preferably in the above range.
  • the upper limit of the cation ratio [Mg2 + /( Mg2 ++ Ca2 ++ Sr2 ++ Ba2 ++Zn2 + )] of the content of Mg2 + to the total content of Mg2 +, Ca2+ , Sr2 + , Ba2+ , and Zn2+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.55, 0.5, 0.45, and 0.4 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28, and 0.3 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Mg2 + /( Mg2 ++Ca2++ Sr2 ++ Ba2 ++Zn2 + )] of the content of Mg2 + to the total content of Mg2 + , Ca2 + , Sr2 + , Ba2+ , and Zn2+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.55, 0.5, 0.45, and 0.4 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28, and 0.3 in that order.
  • the cation ratio may be 0.
  • the cation ratio [Mg 2+ /(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ )] is preferably in the above range.
  • the upper limit of the cation ratio [Ca2 + /( Mg2 ++ Ca2 ++ Sr2 ++ Ba2++ Zn2 +)] of the content of Ca2 + to the total content of Mg2+ , Ca2 + , Sr2 +, Ba2 +, and Zn2+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.1 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Ca2 + /( Mg2 ++ Ca2++ Sr2 ++ Ba2 ++Zn2 + )] of the content of Ca2 + to the total content of Mg2 + , Ca2 + , Sr2 + , Ba2+ , and Zn2+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.1 in this order.
  • the cation ratio may be 0.
  • the cation ratio [Ca 2+ /(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ )] is preferably in the above range.
  • the upper limit of the cation ratio [Sr2 + /( Mg2 ++ Ca2 ++ Sr2 ++ Ba2++ Zn2 +)] of the content of Sr2 + to the total content of Mg2+ , Ca2 + , Sr2 +, Ba2 +, and Zn2+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.1 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Sr2 + /( Mg2 ++ Ca2 ++ Sr2 ++ Ba2 ++Zn2 + )] of the content of Sr2 + to the total content of Mg2+, Ca2 + , Sr2 + , Ba2+ , and Zn2+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.1 in this order.
  • the cation ratio may be 0.
  • the cation ratio [Sr 2+ /(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ )] is preferably in the above range.
  • the lower limit of the cation ratio [Ba2 + /( Mg2 ++ Ca2 ++ Sr2 ++ Ba2 ++Zn2 + )] of the content of Ba2 + to the total content of Mg2 + , Ca2 + , Sr2 + , Ba2 + , and Zn2 + is preferably 0, and more preferably 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, and 0.60 in this order.
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.90, 0.80, 0.75, 0.74, 0.73, 0.72, 0.71, and 0.70 in this order.
  • the cation ratio may be 0.
  • the lower limit of the cation ratio [Ba2 + /( Mg2 ++Ca2++ Sr2 ++Ba2++Zn2 + )] of the content of Ba2 + to the total content of Mg2+ , Ca2 + , Sr2 + , Ba2 + , and Zn2+ is preferably 0, and more preferably 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, and 0.60 in this order.
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.90, 0.80, 0.75, 0.74, 0.73, 0.72, 0.71, and 0.70 in this order.
  • the cation ratio may be 0.
  • the cation ratio [Ba 2+ /(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ )] is preferably in the above range.
  • the upper limit of the cationic ratio [Zn2 + /( Mg2 ++ Ca2 ++ Sr2 ++ Ba2++ Zn2 + )] of the content of Zn2 + to the total content of Mg2+ , Ca2 + , Sr2 +, Ba2 + , and Zn2+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in this order.
  • the lower limit of the cationic ratio is preferably 0, and more preferably 0.05 and 0.1 in this order.
  • the cationic ratio may be 0.
  • the upper limit of the cationic ratio of the content of Zn2+ to the total content of Mg2 + , Ca2 + , Sr2 + , Ba2 + , and Zn2+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in this order.
  • the lower limit of the cationic ratio is preferably 0, and more preferably 0.05 and 0.1 in this order.
  • the cationic ratio may be 0.
  • the cation ratio [Zn 2+ /(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ )] be in the above-mentioned range.
  • the lower limit of the cation ratio [ La3+ / (La3 + + Gd3 + +Y3 + )] of the content of La3+ to the total content of La3+, Gd3 +, and Y3+ is preferably 0, and more preferably 0.05, 0.10, 0.15, 0.20, 0.25, 0.27, 0.29, 0.31, 0.33, 0.35, 0.37, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, and 0.45, in that order.
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.59, 0.58, 0.57, 0.56, 0.55, 0.54, and 0.53 in that order.
  • the lower limit of the cationic ratio of the content of La3 + to the total content of La3 + , Gd3 + , and Y3+ [La3 + /( La3 ++ Gd3 ++ Y3+ )] is preferably 0, and more preferably 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.62, 0.64, 0.66, and 0.68 in this order.
  • the upper limit of the cationic ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.78, 0.76, 0.74, and 0.72 in this order.
  • the cation ratio [La 3+ /(La 3+ +Gd 3+ +Y 3+ )] be in the above range.
  • the upper limit of the cationic ratio [ Gd3 + /( La3 ++ Gd3 ++Y3+)] of the content of Gd3 + to the total content of La3+, Gd3 + , and Y3 + is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.55, 0.50, 0.45, 0.40, 0.35, 0.30, 0.25, 0.20, 0.15, and 0.10 in this order.
  • the lower limit of the cationic ratio is preferably 0, and more preferably 0.01 and 0.05 in this order.
  • the cationic ratio may be 0.
  • the upper limit of the cation ratio [Gd3 + /(La3 + + Gd3 + +Y3+)] of the Gd3 + content to the total content of La3+, Gd3 + , and Y3 + is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.55, 0.50, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, and 0.32 , in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.05, 0.10, 0.15, 0.20, 0.22, 0.24, 0.26, and 0.28 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Y3 + /( La3 ++ Gd3 ++Y3+)] of the content of Y3 + to the total content of La3 + , Gd3 +, and Y3 + is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.63, 0.61, 0.60, 0.59, 0.58, 0.57, 0.56, and 0.55, in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, 0.15, 0.20, 0.25, 0.27, 0.29, 0.31, 0.33, 0.35, 0.37, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, and 0.48 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cationic ratio [Y3 + /( La3 ++ Gd3 ++ Y3+ )] of the content of Y3 + to the total content of La3 + , Gd3 + , and Y3+ is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.55, 0.50, 0.45, 0.40, 0.35, 0.30, 0.25, 0.20, 0.15, 0.10, and 0.05 in this order.
  • the lower limit of the cationic ratio is preferably 0, and more preferably 0.01, 0.02, and 0.03 in this order.
  • the cationic ratio may be 0.
  • the cation ratio [Y 3+ /(La 3+ +Gd 3+ +Y 3+ )] be in the above range.
  • the upper limit of the cation ratio [Ti4 + /(Ti4 + + Nb5+ + W6 + +Bi3 + )] of the Ti4 + content to the total content of Ti4+, Nb5 + , W6+, and Bi3 + is preferably 1, and more preferably 0.9, 0.8 , 0.7, 0.6, 0.5, 0.45, 0.4, 0.35 , 0.3, 0.25, 0.23, 0.21, 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, and 0.11, in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, and 0.08 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Ti4 + /(Ti4 + + Nb5 + + W6 + +Bi3 + )] of the content of Ti4 + to the total content of Ti4+, Nb5 +, W6 + , and Bi3 + is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.23, 0.21, 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, and 0.11, in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, and 0.08 in that order.
  • the cation ratio may be 0.
  • the cation ratio [Ti 4+ /(Ti 4+ +Nb 5+ +W 6+ +Bi 3+ )] be in the above range.
  • the upper limit of the cation ratio [Nb5 + /(Ti4 + + Nb5 + +W6 + +Bi3 + )] of the Nb5 + content to the total content of Ti4+, Nb5+, W6 + , and Bi3 + is preferably 1, and more preferably 0.95, 0.90, 0.85 , 0.80, 0.75, 0.74, 0.73, 0.72, 0.71, 0.70, 0.69, 0.68, and 0.67, in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, and 0.62 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [ Nb5 + /(Ti4 + + Nb5 + + W6 + +Bi3 + )] of the content of Nb5 + to the total content of Ti4+, Nb5 +, W6+ , and Bi3+ is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.74, 0.73, 0.72, 0.71, 0.70, 0.69, 0.68, and 0.67 , in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, and 0.62 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [W6 + /(Ti4 + + Nb5+ + W6 + +Bi3+)] of the content of W6 + to the total content of Ti4 + , Nb5 +, W6 + , and Bi3+ is preferably 1, and more preferably 0.9, 0.8 , 0.7, 0.6, 0.5, 0.45, 0.44, 0.43, 0.42, 0.41, 0.40, 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32, 0.31, 0.3, 0.29, 0.28, and 0.27 , in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, 0.12, 0.14, 0.16, 0.18, 0.20, 0.21, 0.22, 0.23, and 0.24 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [W6 + /(Ti4 + + Nb5 + + W6 + +Bi3 + )] of the content of W6 + to the total content of Ti4+, Nb5 +, W6+, and Bi3 + is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.44, 0.43, 0.42, 0.41, 0.40, 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32, 0.31, 0.3, 0.29, 0.28, and 0.27, in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, 0.12, 0.14, 0.16, 0.18, 0.20, 0.21, 0.22, 0.23, and 0.24 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Bi3 + /(Ti4 + + Nb5+ + W6+ + Bi3 + )] of the Bi3 + content to the total content of Ti4+, Nb5+, W6 + , and Bi3+ is preferably 1, and more preferably 0.9, 0.8 , 0.7, 0.6, 0.5, 0.45, 0.44, 0.43, 0.42, 0.41, 0.40, 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32, 0.31, 0.3, 0.29, 0.28, and 0.27, in that order.
  • the lower limit of the cation ratio is preferably 0, and may be 0.05, 0.1, 0.12, 0.14, 0.16, 0.18, 0.20, 0.21, 0.22, 0.23, or 0.24.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Bi3 + /(Ti4 + + Nb5+ + W6 + +Bi3 + )] of the content of Bi3 + to the total content of Ti4+, Nb5 +, W6 + , and Bi3 + is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.44, 0.43, 0.42, 0.41, 0.40, 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32, 0.31, 0.3, 0.29, 0.28, and 0.27, in that order.
  • the lower limit of the cation ratio is preferably 0, and may be 0.05, 0.1, 0.12, 0.14, 0.16, 0.18, 0.20, 0.21, 0.22, 0.23, or 0.24.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [ Zr4 + /( Zr4 ++Ta5 + )] of the content of Zr4 + to the total content of Zr4+ and Ta5 + is preferably 1, and more preferably 0.95, 0.90, and 0.85 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.5, 0.6, 0.7, and 0.8 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio of the content of Zr4 + to the total content of Zr4 + and Ta5+ [Zr4 + /(Zr4++Ta5 + )] is preferably 1, and more preferably 0.95, 0.90 , and 0.85 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.5, 0.6, 0.7, and 0.8 in that order.
  • the cation ratio may be 0.
  • the cation ratio [Zr 4+ /(Zr 4+ +Ta 5+ )] is within the above range.
  • the upper limit of the cation ratio [ Ta5 + /( Zr4 ++ Ta5+ )] of the content of Ta5 + to the total content of Zr4+ and Ta5+ is preferably 1, and more preferably 0.5, 0.4, 0.3, and 0.2 in that order.
  • the lower limit of the cation ratio is preferably 0, and may be 0.05, 0.10, or 0.15.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio of the content of Ta5 + to the total content of Zr4 + and Ta5 + [Ta5 + /( Zr4 ++ Ta5+ )] is preferably 1, and more preferably 0.5, 0.4, 0.3, and 0.2 in that order.
  • the lower limit of the cation ratio is preferably 0, and may be 0.05, 0.10, or 0.15.
  • the cation ratio may be 0.
  • the cation ratio [Ta 5+ /(Zr 4+ +Ta 5+ )] is within the above range.
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.23, 0.21, 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.10, 0.09, 0.08, 0.07, 0.06 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04 in that order.
  • the cation ratio may be 0.
  • the cation ratio of the content of Ti4 + to the total content of Ti4 + , Nb5 + , Bi3 + , W6 + , Zr4 + , and Ta5 + [ Ti4 + /(Ti4++ Nb5 ++ Bi3 ++ W6 ++ Zr4 ++Ta5 +
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.23, 0.21, 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.10, 0.09, 0.08, 0.07, 0.06 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04 in that order.
  • the cation ratio may be 0.
  • the cation ratio [Ti 4+ /(Ti 4+ +Nb 5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+ )] be within the above range.
  • the upper limit of the cation ratio [Nb5 + /(Ti4 + + Nb5+ +Bi3+ +W6+ +Zr4+ +Ta5 + )] of the content of Nb5 + to the total content of Ti4+, Nb5 + , Bi3 + , W6 + , Zr4 + , and Ta5+ is preferably 1, and more preferably 0.95, 0.90 , 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.55, 0.50, 0.45, 0.40, 0.35, 0.34, 0.33 , 0.32 , 0.31, 0.30, 0.29, 0.28, and 0.27 , in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, and 0.24 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Nb5 + /(Ti4 + +Nb5 + +Bi3 + +W6 + + Zr4+ + Ta5 +) ] of the content of Nb5 + to the total content of Ti4 + , Nb5 + , Bi3 + , W6 + , Zr4+, and Ta5+ is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.55 , 0.50, 0.45, 0.40, 0.35, 0.34, 0.33, 0.32, 0.31, 0.30, 0.29, 0.28, and 0.27 , in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, and 0.24 in that order.
  • the cation ratio may be 0.
  • the cation ratio [Nb 5+ /(Ti 4+ +Nb 5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+ )] be within the above range.
  • the cation ratio of the content of Bi 3+ to the total content of Ti 4+ , Nb 5+ , Bi 3+ , W 6+ , Zr 4+ , and Ta 5+ [Bi 3+ /(Ti 4+ + Nb 5+ + Bi 3+ + W 6+ + Zr 4+ + Ta 5+
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.35, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, 0.20, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11.
  • the lower limit of the cation ratio is preferably 0, and may be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, or 0.09.
  • the cation ratio may be 0.
  • the cation ratio of the content of Bi 3+ to the total content of Ti 4+ , Nb 5+ , Bi 3+ , W 6+ , Zr 4+ , and Ta 5+ [Bi 3+ /(Ti 4+ + Nb 5+ + Bi 3+ + W 6+ + Zr 4+ + Ta 5+
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.35, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, 0.20, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11.
  • the lower limit of the cation ratio is preferably 0, and may be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, or 0.09.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.35, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, 0.20, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.35, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, 0.20, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09 in this order.
  • the upper limit of the cation ratio [Zr4 + /( Ti4 ++ Nb5 ++Bi3 ++ W6 ++Zr4++Ta5 + )] of the content of Zr4 + to the total content of Ti4+, Nb5 + , Bi3 + , W6 + , Zr4+, and Ta5+ is preferably 1, and more preferably 0.95, 0.9, 0.85, 0.80, 0.75, 0.70, 0.69, 0.68, 0.67, 0.66, 0.65, 0.64, 0.63, and 0.62 , in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.1, 0.2, 0.3, 0.4, 0.45, 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, and 0.58 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Zr4 + /( Ti4 ++ Nb5 ++Bi3++ W6 ++ Zr4 ++Ta5 +) ] of the content of Zr4 + to the total content of Ti4+, Nb5 + , Bi3 + , W6 + , Zr4 + , and Ta5+ is preferably 1, and more preferably 0.95, 0.9, 0.85, 0.80, 0.75, 0.70, 0.69, 0.68, 0.67, 0.66, 0.65, 0.64, 0.63, and 0.62 , in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.1, 0.2, 0.3, 0.4, 0.45, 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, and 0.58 in that order.
  • the cation ratio may be 0.
  • the cation ratio [Zr4 + /( Ti4 ++ Nb5 ++ Bi3 ++ W6 ++ Zr4 ++Ta5 + )] be in the above range.
  • the upper limit of the cation ratio [Ta5 + /( Ti4 ++ Nb5 ++ Bi3++ W6 ++ Zr4 ++Ta5 + )] of the content of Ta5 + to the total content of Ti4+, Nb5 +, Bi3 +, W6 +, Zr4 + , and Ta5+ is preferably 1, and more preferably 0.5, 0.4, 0.3, 0.25, 0.2, 0.15, 0.1, 0.08, 0.06, and 0.04 in this order.
  • the lower limit of the cation ratio is preferably 0, and may be 0.01, 0.02, or 0.03.
  • the cation ratio may be 0.
  • the upper limit of the cationic ratio [Ta5 + /( Ti4 ++ Nb5 ++Bi3++W6++ Zr4 ++Ta5 + )] of the content of Ta5+ to the total content of Ti4+ , Nb5+ , Bi3 + , W6+ , Zr4 + , and Ta5+ is preferably 1, and more preferably 0.5, 0.4, 0.3, 0.25, 0.2, 0.15, 0.1, 0.08, 0.06, and 0.04 in that order.
  • the lower limit of the cationic ratio is preferably 0, and may be 0.01, 0.02, or 0.03.
  • the cationic ratio may be 0.
  • the cation ratio [Ta 5+ /(Ti 4+ +Nb 5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+ )] is within the above range.
  • the upper limit of the cation ratio [ Al3+ / (Si4++ B3+ ) ] of the content of Al3 + to the total content of Si4 + and B3+ is preferably 0.5, and more preferably 0.45, 0.40, 0.35, 0.30, 0.25, and 0.20 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.05, 0.1, and 0.15 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio of the content of Al 3+ to the total content of Si 4+ and B 3+ [Al 3+ /(Si 4+ +B 3+ )] is preferably 0.5, and more preferably 0.45, 0.40, 0.35, 0.30, 0.25, and 0.20 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.05, 0.1, and 0.15 in that order.
  • the cation ratio may be 0.
  • cation ratio [Al 3+ /(Si 4+ +B 3+ )] can improve the mechanical properties and chemical durability of the glass. On the other hand, if the cation ratio is too high, the liquidus temperature rises and the thermal stability of the glass is impaired. From the viewpoint of maintaining the thermal stability of the glass, it is preferable to set the cation ratio within the above range.
  • the upper limit of the cation ratio [Al3 + /(Li + Na + K + )] of the content of Al3 + to the total content of Li + , Na + , and K + is preferably 2, and more preferably 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, and 0.2 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Al3 + / (Li + Na + K + )] of the content of Al3+ to the total content of Li + , Na+, and K+ is preferably 2, and more preferably 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, and 0.2 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15 in this order.
  • the cation ratio may be 0.
  • the mechanical properties and chemical durability of the glass can be improved.
  • the cation ratio is too high, the liquidus temperature rises and the thermal stability of the glass is impaired. From the viewpoint of maintaining the thermal stability of the glass, it is preferable to set the cation ratio within the above range.
  • the upper limit of the cation ratio [Al 3+ /(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ )] of the content of Al 3+ to the total content of Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ is preferably 5, and more preferably 4.0, 3.5, 3, 2.5, 2.0, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.3, 0.2 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, 0.15 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Al3 + /( Mg2 ++ Ca2 ++ Sr2 ++Ba2 + )] of the content of Al3 + to the total content of Mg2 + , Ca2 +, Sr2+ , and Ba2+ is preferably 2, and more preferably 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.3, and 0.2 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15 in that order.
  • the cation ratio may be 0.
  • the mechanical properties and chemical durability of the glass can be improved.
  • the cation ratio is too high, the liquidus temperature rises and the thermal stability of the glass is impaired. From the viewpoint of maintaining the thermal stability and devitrification resistance of the glass, it is preferable to set the cation ratio within the above range.
  • the upper limit of the cation ratio [Al 3+ / (Li + Na + K + Mg 2+ + Ca 2+ + Sr 2+ + Ba 2+ )] of the content of Al 3+ to the total content of Li + , Na + , K + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ is preferably 5, and more preferably 4, 3, 2, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.3, and 0.2 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Al 3+ / (Li + Na + K + Mg 2+ + Ca 2+ + Sr 2+ + Ba 2+ )] of the content of Al 3+ to the total content of Li + , Na + , K + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ is preferably 5, and more preferably 4, 3, 2, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.3, and 0.2 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15 in this order.
  • the cation ratio may be 0.
  • the mechanical properties and chemical durability of the glass can be improved.
  • the cation ratio is too high, the liquidus temperature rises and the thermal stability of the glass is impaired. From the viewpoint of maintaining the thermal stability and devitrification resistance of the glass, it is preferable to set the cation ratio within the above range.
  • the upper limit of the cation ratio [Al3 + /( La3 ++ Gd3 ++Y3+)] of the content of Al3 + to the total content of La3 + , Gd3 +, and Y3 + is preferably 2, and more preferably 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.3, and 0.2 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [Al3 + /( La3 ++ Gd3 ++Y3+)] of the content of Al3+ to the total content of La3 +, Gd3+ , and Y3 + is preferably 2, and more preferably 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.3, and 0.2 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15 in this order.
  • the cation ratio may be 0.
  • the cation ratio [Al 3+ /(La 3+ +Gd 3+ +Y 3+ )] be in the above range.
  • the upper limit of the cation ratio [(Li + Na + K + )/(Si 4+ + B 3+ )] of the total content of Li + , Na + , and K + to the total content of Si 4+ and B 3+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.35, 0.3, 0.25, 0.24, 0.23, 0.22, and 0.21 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.07, 0.09, 0.10, 0.11, 0.12, 0.13, and 0.14 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [(Li + Na + K + )/(Si 4+ + B 3+ )] of the total content of Li + , Na + , and K + to the total content of Si 4+ and B 3+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.09, 0.08, 0.07, and 0.06 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, and 0.05 in this order.
  • the cation ratio may be 0.
  • the cation ratio [(Li + +Na + +K + )/(Si 4+ +B 3+ )] be in the above-mentioned range.
  • the upper limit of the cation ratio [( Mg2 + + Ca2 + + Sr2+ + Ba2+)/( Si4 + + B3 + )] of the total content of Mg2+, Ca2 + , Sr2 + , and Ba2 + to the total content of Si4+ and B3+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.48 , 0.46, 0.45, 0.44, 0.43, 0.42, 0.41, 0.40, and 0.39, in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, and 0.35 in that order.
  • the upper limit of the cation ratio of the total content of Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ to the total content of Si 4+ and B 3+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14 and 0.12, in that order.
  • the lower limit of the cation ratio is preferably 0.01, and more preferably 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, and 0.10 in that order.
  • the lower limit of the cation ratio [(Li + Na + K + Mg 2+ + Ca 2+ + Sr 2+ + Ba 2+ )/(Si 4+ + B 3+ )] of the total content of Li + , Na + , K + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ to the total content of Si 4+ and B 3+ is preferably 0, and more preferably 0.01, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.46, 0.47 , 0.48 , 0.49, 0.50, 0.51, and 0.52 in that order.
  • the upper limit of the cation ratio is preferably 2, and more preferably 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.68, 0.66, 0.64, 0.62, 0.61, and 0.6 in that order.
  • the cation ratio may be 0.
  • the lower limit of the cation ratio of the total content of Li + , Na + , K + , Mg2+ , Ca2 + , Sr2 + , and Ba2 + to the total content of Si4+ and B3+ is preferably 0.01, and more preferably is 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, and 0.10, in that order.
  • the upper limit of the cation ratio is preferably 2, and more preferably 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, and 0.12 in that order.
  • the lower limit of the cation ratio [(La3 + + Gd3+ + Y3+ )/( Si4 + + B3 + )] of the total content of La3 + , Gd3 + , and Y3 + to the total content of Si4+ and B3+ is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.93, 0.94, and 0.95, in that order.
  • the upper limit of the cation ratio is preferably 3, and more preferably 2.5, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.13, 1.11, 1.10, and 1.09 in that order.
  • the lower limit of the cation ratio of the total content of La 3+ , Gd 3+ and Y 3+ to the total content of Si 4+ and B 3+ [(La 3+ + Gd 3+ + Y 3+ )/(Si 4+ + B 3+ )] is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.93, 0.94 and 0.95 in that order.
  • the upper limit of the cation ratio is preferably 3, and more preferably 2.5, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.13, 1.11, 1.10, and 1.09 in that order.
  • the cation ratio [(La 3+ +Gd 3+ +Y 3+ )/(Si 4+ +B 3+ )] be in the above range.
  • the lower limit of the cation ratio is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, and 1.55.
  • the upper limit of the cation ratio is preferably 4, and more preferably 3, 2.5, 2.2, 2.0, 1.95, 1.90, 1.85, 1.80, 1.78, 1.76, 1.74, 1.72, 1.70, 1.68, 1.66, 1.64, and 1.62.
  • the lower limit of the cation ratio is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.05, 1.10, 1.13, and 1.15 in that order.
  • the upper limit of the cation ratio is preferably 4, and more preferably 3, 2.5, 2.2, 2.0, 1.95, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, 1.60, 1.55, 1.50, 1.45, 1.40, 1.35, 1.30, 1.25, and 1.20 in that order.
  • the upper limit of the cation ratio [( Ti4 +Nb5++W6+Bi3 +)/(Si4++B3+ ) ] of the total content of Ti4+ , Nb5 + , W6 + , and Bi3 + to the total content of Si4 + and B3+ is preferably 0.5, and more preferably 0.4, 0.3, 0.2, and 0.1 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, and 0.04 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [( Ti4 + Nb5 ++W6++Bi3 + )/( Si4 ++B3 + )] of the total content of Ti4 + , Nb5+ , W6 + , and Bi3 + to the total content of Si4+ and B3+ is preferably 0.5, and more preferably 0.4, 0.3, 0.2, and 0.1 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, and 0.04 in that order.
  • the cation ratio may be 0.
  • the cation ratio [(Ti 4+ +Nb 5+ +W 6+ +Bi 3+ )/(Si 4+ +B 3+ )] be within the above range.
  • the upper limit of the cation ratio [( Zr4 + + Ta5 + )/( Si4+ + B3 + )] of the total content of Zr4+ and Ta5 + to the total content of Si4+ and B3+ is preferably 0.5, more preferably 0.4, 0.3, 0.2, and 0.1 in this order.
  • the lower limit of the cation ratio is preferably 0, more preferably 0.01, 0.02, 0.03, and 0.04 in this order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio of the total content of Zr4 + and Ta5 + to the total content of Si4 + and B3 + [( Zr4 + + Ta5 + )/( Si4+ + B3 + )] is preferably 0.5, and more preferably 0.4, 0.3, 0.2, and 0.1 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, and 0.04 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [(Li + Na+K + )/( Si4 ++ B3 ++ Ti4 ++ Nb5 ++ W6 ++Bi3 + )] of the total content of Li + , Na + , and K + to the total content of Si4 + , B3+, Ti4+ , Nb5 + , W6 + , and Bi3+ is preferably 1, and more preferably 0.9, 0.8, 0.7 , 0.6, 0.5 , 0.4, 0.35, 0.3, 0.25, 0.24, 0.23, 0.22, and 0.21 in this order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.07, 0.09, 0.10, 0.11, 0.12, 0.13, and 0.14 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [(Li + Na + K + )/( Si4 ++ B3 ++ Ti4 ++ Nb5 ++ W6 ++Bi3 +) ] of the total content of Li + , Na + , and K + to the total content of Si4 +, B3+, Ti4 +, Nb5+, W6 + , and Bi3+ is preferably 1, and more preferably 0.9, 0.8, 0.7 , 0.6 , 0.5, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.09, 0.08, 0.07, and 0.06 , in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, and 0.05 in that order.
  • the cation ratio may be 0.
  • the cation ratio [(Li + +Na + +K + )/(Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ )] is preferable for the cation ratio [(Li + +Na + +K + )/(Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ )] to be in the above-mentioned range.
  • the upper limit of the cation ratio [(Mg2 + + Ca2+ + Sr2+ + Ba2+)/(Si4 + + B3 + + Ti4 + + Nb5+ + W6+ + Bi3 +) ] of the total content of Mg2 +, Ca2 + , Sr2 + , and Ba2 + to the total content of Si4+, B3 + , Ti4 + , Nb5 +, W6+ , and Bi3 + is preferably 1, and more preferably 0.9, 0.8 , 0.7, 0.6, 0.5, 0.48, 0.46, 0.45, 0.44, 0.43, 0.42, 0.41, 0.40, and 0.39 , in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, and 0.35 in that order.
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, and 0.12 in that order.
  • the lower limit of the cation ratio is preferably 0.01, and more preferably 0.02,
  • the cation ratio [( Mg2 + + Ca2 + + Sr2 + +Ba2 + )/( Si4 + + B3 + + Ti4 + + Nb5 + + W6 + +Bi3 + )] within the above range.
  • the cation ratio of the total content of Li + , Na + , K + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ to the total content of Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ is [(Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ )/(Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52 in this order.
  • the upper limit of the cation ratio is preferably 2, and more preferably 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.68, 0.66, 0.64, 0.62, 0.61, 0.6 in this order.
  • the cation ratio may be 0.
  • the cation ratio of the total content of Li + , Na + , K + , Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ to the total content of Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ and Bi 3+ is set to [(Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2 + )/(Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+
  • the lower limit of the cation ratio is preferably 0.01, and more preferably 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, and 0.10 in that order.
  • the upper limit of the cation ratio is preferably 2, and more preferably 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, and 0.12 in that order.
  • the cation ratio of the total content of La 3+ , Gd 3+ , and Y 3+ to the total content of Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ [(La 3+ + Gd 3+ + Y 3+ )/(Si 4+ + B 3+ + Ti 4+ + Nb 5+ + W 6+ + Bi 3+
  • the lower limit of the cation ratio is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.93, 0.94, and 0.95 in that order.
  • the upper limit of the cation ratio is preferably 3, and more preferably 2.5, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.13, 1.11, 1.10, and 1.09 in that order.
  • the cation ratio of the total content of La 3+ , Gd 3+ and Y 3+ to the total content of Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ and Bi 3+ is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.93, 0.94, and 0.95 in that order.
  • the upper limit of the cation ratio is preferably 3, and more preferably 2.5, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.13, 1.11, 1.10, 1.09, 1.08, 1.07, 1.06, and 1.05 in that order.
  • the cation ratio [( La3 + + Gd3 + + Y3 + )/( Si4 + + B3 + + Ti4 + + Nb5 + + W6 + + Bi3 + )] be in the above range.
  • the cation ratio of the total content of Li + , Na + , K + , Mg2 +, Ca2 + , Sr2 + , Ba2 + , La3 + , Gd3+ , and Y3 + to the total content of Si4 + , B3 + , Ti4 + , Nb5+, W6+, and Bi3 + is [(Li ++ Na ++ K ++ Mg2 ++ Ca2 ++Sr2++Ba2++La3++ Gd3 ++ Y3+ )/( Si4 ++ B3 ++ Ti4 ++ Nb5 ++ W6 ++Bi3 +
  • the lower limit of the cation ratio is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, and 1.55.
  • the upper limit of the cation ratio is preferably 4, and more preferably 3, 2.5, 2.2, 2.0, 1.95, 1.90, 1.85, 1.80, 1.78, 1.76, 1.74, 1.72, 1.70, 1.68, 1.66, 1.64, and 1.62.
  • the cation ratio of the total content of Li + , Na + , K + , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , La 3+ , Gd 3+ , and Y 3+ to the total content of Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ is [(Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +La 3+ +Gd 3+ +Y 3+ )/(Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+
  • the lower limit of the cation ratio is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.02, 1.04, 1.06,
  • the upper limit of the cation ratio is preferably 4, and more preferably 3, 2.5, 2.2, 2.0, 1.95, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, 1.60, 1.55, 1.50, 1.45, 1.40, 1.35, 1.30, 1.25, 1.20, and 1.15 in that order.
  • the upper limit of the cation ratio [(Li +Na+K+)/(Si4++B3++Ti4++Nb5++W6++Bi3++Zr4++Ta5+)] of the total content of Li+ , Na+, and K+ to the total content of Si4 + , B3 + , Ti4 + , Nb5+ , W6 + , Bi3 + , Zr4 + , and Ta5+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4 , 0.35, 0.3 , 0.25, 0.24, 0.23, 0.22 , and 0.21 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.07, 0.09, 0.10, 0.11, 0.12, 0.13, and 0.14 in that order.
  • the cation ratio may be 0.
  • the upper limit of the cation ratio [(Li + Na + K+)/( Si4 ++ B3 ++Ti4 ++ Nb5 ++ W6 ++ Bi3 ++ Zr4 ++Ta5 +) ] of the total content of Li + , Na + , and K + to the total content of Si4 + , B3+, Ti4 + , Nb5 + , W6 + , Bi3 + , Zr4+ , and Ta5+ is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5 , 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.09, 0.08, 0.07, and 0.06 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, and 0.05 in that order.
  • the cation ratio may be 0.
  • the cation ratio [(Li + +Na + +K + )/(Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+ )] is preferable for the cation ratio [(Li + +Na + +K + )/(Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+ )] to be in the above-mentioned range.
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.45, 0.44, 0.43, 0.42, 0.41, 0.40, and 0.39 in that order.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, and 0.35 in that order.
  • the upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, and 0.12 in that order.
  • the cation ratio [( Mg2 + + Ca2 + + Sr2 + +Ba2 + )/( Si4 + + B3 + + Ti4 + + Nb5 + + W6 + + Bi3 + + Zr4 + +Ta5 + )] within the above range.
  • the lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52 in this order.
  • the upper limit of the cation ratio is preferably 2, and more preferably 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.68, 0.66, 0.64, 0.62, 0.61, 0.6 in this order.
  • the cation ratio may be 0.
  • the lower limit of the cation ratio is preferably 0.01, and more preferably 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, and 0.09 in that order.
  • the upper limit of the cation ratio is preferably 2, and more preferably 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, and 0.12 in that order.
  • the cation ratio of the total content of La 3+ , Gd 3+ , and Y 3+ to the total content of Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ , and Ta 5+ [(La 3+ + Gd 3+ + Y 3+ )/(Si 4+ + B 3+ + Ti 4+ + Nb 5+ + W 6+ + Bi 3+ + Zr 4+ + Ta 5+
  • the lower limit of the cation ratio is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.93, 0.94, and 0.95 in that order.
  • the upper limit of the cation ratio is preferably 3, and more preferably 2.5, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.13, 1.11, 1.10, and 1.09 in that order.
  • the cation ratio of the total content of La 3+ , Gd 3+ and Y 3+ to the total content of Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ and Ta 5+ is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, and 0.93 in that order.
  • the upper limit of the cation ratio is preferably 3, and more preferably 2.5, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.13, 1.11, 1.10, 1.09, 1.08, 1.07, 1.06, 1.05, 1.04, 1.03, 1.02, 1.01, 1.00, 0.99, 0.98, 0.97, 0.96, and 0.95 in that order.
  • the cation ratio of the total content of Li + , Na + , K + , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , La 3+ , Gd 3+ , and Y 3+ to the total content of Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ , and Ta 5+ is [ ( Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +La 3+ +Gd 3+ +Y 3+ )/(Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+ ) is preferably 0.50, and more preferably 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20,
  • the upper limit of the cation ratio is preferably 5.00, and more preferably 4.00, 3.00, 2.50, 2.30, 2.20, 2.10, 2.00, 1.95, 1.90, 1.85, 1.80, 1.78, 1.76, 1.74, 1.72, 1.70, 1.68, 1.66, 1.64, and 1.62 in that order.
  • the lower limit of the cation ratio is preferably 0.01 , and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90,
  • the upper limit of the cation ratio is preferably 4, and more preferably 3, 2.5, 2.2, 2.0, 1.95, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, 1.60, 1.55, 1.50, 1.45, 1.40, 1.35, 1.30, 1.25, 1.20, 1.15, 1.13, 1.11, 1.10, 1.09, 1.08, 1.07, and 1.06 in that order.
  • the cation ratio of the total content of La3 + , Gd3 + , Y3+ , Li + , Na + , K + , Rb + , Cs + , Mg2+ , Ca2 + , Sr2 + , and Ba2 + to the total content of Si4 +, B3 + , P5 + , Ti4 + , Nb5 + , W6 + , Bi3 + , Zr4+, and Ta5+ is [( La3 + + Gd3 + + + Y3 + + Li + + Na + + K + + + Rb + + Cs + + Mg2 + + Ca2 + + Sr2 + + Ba2 + )/( Si4 + + B3 + + P5 + + Ti4 + + Nb
  • the lower limit of the ratio [ (Bi3 + + W6 + + Bi3 + + Zr4 + + Ta5 + )] is preferably 0.50, and more preferably 0.55, 0.60, 0.65, 0.70,
  • the upper limit of the cation ratio is preferably 5.00, and more preferably 4.00, 3.00, 2.50, 2.30, 2.20, 2.10, 2.00, 1.95, 1.90, 1.85, 1.80, 1.78, 1.76, 1.74, 1.72, 1.70, 1.68, 1.66, 1.64, and 1.62 in that order.
  • the cation ratio of the total content of La 3+ , Gd 3+ , Y 3+ , Li + , Na + , K + , Rb + , Cs + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ to the total content of Si 4+ , B 3+ , P 5+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ , and Ta 5+ is set to be [(La 3+ + Gd 3+ + Y 3+ + Li + + Na + + K + + + Rb + + Cs + Mg 2+ + Ca 2+ + Sr 2+ + Ba 2+ )/(Si 4+ + B 3+ + P 5+ + Ti
  • the lower limit of the ratio [ (Nb4 + + Nb5 + + W6 + + Bi3 + + Zr4 + + Ta5 + )] is
  • the upper limit of the cation ratio is preferably 5.00, and more preferably 4.00, 3.00, 2.50, 2.30, 2.10, 2.00, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, 1.60, 1.55, 1.50, 1.45, 1.40, 1.35, 1.30, 1.25, 1.20, 1.15, and 1.10, in that order.
  • the cation ratio [( La3 ++ Gd3 ++ Y3 ++ Li++Na ++ K ++ Rb ++ Cs ++ Mg2 ++ Ca2 ++Sr2++ Ba2 + )/( Si4 ++ B3 ++ P5++Ti4++ Nb5 ++ W6 ++ Bi3 ++ Zr4 ++ Ta5 + )] is too small, the volatilization of glass components may increase. If the cation ratio is too large, the thermal stability of the glass may decrease. From the viewpoint of suppressing the volatilization of glass components, it is preferable to set the cation ratio within the above range.
  • the upper limit of the P5 + content is preferably 30%, and more preferably 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, and 1% in that order.
  • the lower limit of the P5 + content is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5% in that order.
  • the P5+ content may be 0%.
  • the upper limit of the P5 + content is preferably 30%, and more preferably 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, and 1% in that order.
  • the lower limit of the P5 + content is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5% in that order.
  • the P5+ content may be 0%.
  • the upper limit of the Al 3+ content is preferably 30%, and more preferably 20%, 13%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, and 1% in that order.
  • the lower limit of the Al 3+ content is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5% in that order.
  • the Al 3+ content may be 0%.
  • the upper limit of the Al 3+ content is preferably 30%, and more preferably 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, and 1% in that order.
  • the lower limit of the Al 3+ content is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5% in that order.
  • the Al 3+ content may be 0%.
  • the content of Al 3+ is within the above range.
  • the Si4 + content is preferably more than 0%, with the lower limit being preferably 1%, and more preferably 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10% in that order.
  • the upper limit of the Si4 + content is preferably 30%, and more preferably 25%, 23%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, and 13% in that order.
  • the content of Si4 + is preferably more than 0%, and the lower limit is preferably 1%, and more preferably 1.5%, 2%, 2.5%, 3%, 3.5%, and 4% in that order.
  • the upper limit of the content of Si4 + is preferably 30%, and more preferably 25%, 23%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, and 7% in that order.
  • Si4 + is a network forming component of glass. If the content of Si4+ is too low, the chemical durability, mechanical properties, and thermal stability of the glass may be reduced. If the content of Si4+ is too high, the melting property of the glass may be reduced, and the refractive index nd may be reduced. In addition, the thermal stability of the glass may be reduced, and the glass transition temperature Tg may be increased. Therefore, from the viewpoint of obtaining an optical glass having abnormal partial dispersion and improved chemical durability, mechanical properties, and thermal stability, it is preferable to set the content of Si4 + to the above range.
  • the upper limit of the Li + content is preferably 40%, and more preferably 30%, 20%, 17%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, and 8% in this order.
  • the lower limit of the Li + content is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 4.5%, 5%, 5.5%, 6%, and 6.5% in this order.
  • the Li + content may be 0%.
  • the upper limit of the Li + content is preferably 40%, and more preferably 30%, 20%, 17%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, and 2% in that order.
  • the lower limit of the Li + content is preferably 0%, and more preferably 0.01%, 0.05%, 0.1%, 0.5%, and 1% in that order.
  • the Li + content may be 0%.
  • Li + is a component that contributes to lowering the viscosity of glass. If the content of Li + is too high, the thermal stability of the glass and the stability during reheating may decrease. If the content of Li + is too low, the glass transition temperature Tg may increase. Therefore, the content of Li + is preferably within the above range.
  • the upper limit of the Na + content is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5% in that order.
  • the lower limit of the Na + content is preferably 0%, and more preferably 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, and 0.35% in that order.
  • the Na + content may be 0%.
  • the upper limit of the Na + content is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5% in that order.
  • the lower limit of the Na + content is preferably 0%, and more preferably 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, and 0.35% in that order.
  • the Na + content may be 0%.
  • Na + is a component that contributes to lowering the viscosity of glass, similar to Li + . If the content of Na + is too high, the thermal stability of the glass and the stability during reheating may be reduced. Therefore, the content of Na + is preferably within the above range.
  • the upper limit of the K + content is preferably 40%, more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5% in this order.
  • the lower limit of the K + content is preferably 0%, more preferably 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35% in this order.
  • the K + content may be 0%.
  • the upper limit of the K + content is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5% in that order.
  • the lower limit of the K + content is preferably 0%, and more preferably 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, and 0.35% in that order.
  • the K + content may be 0%.
  • K + has the function of lowering the liquidus temperature and improving the thermal stability of glass. On the other hand, if the content of K + is too high, the chemical durability, weather resistance, and stability during reheating are reduced. Therefore, the content of K + is preferably within the above range.
  • the upper limit of the Rb + content is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5%, in that order.
  • the lower limit of the Rb + content is preferably 0%.
  • the Rb + content may be 0%.
  • the upper limit of the content of Rb + is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5% in that order.
  • the lower limit of the content of Rb + is preferably 0%.
  • the content of Rb + may be 0%.
  • the content of Rb + is too high, the volatilization of glass components during melting increases, making it impossible to obtain the desired glass.
  • the content of Rb + is preferably within the above range.
  • the upper limit of the Cs + content is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5% in that order.
  • the lower limit of the Cs + content is preferably 0%.
  • the Cs + content may be 0%.
  • the upper limit of the Cs + content is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5% in that order.
  • the lower limit of the Cs + content is preferably 0%.
  • the Cs + content may be 0%.
  • the Cs + content is high, the volatilization of glass components during melting increases, making it impossible to obtain the desired glass. In addition, there is a risk of the chemical durability and weather resistance decreasing. Therefore, it is preferable that the Cs + content is within the above range.
  • the upper limit of the Mg2 + content is preferably 40%, and more preferably 30%, 20%, 15%, 13%, 11%, 10%, 9%, 8%, 7%, 6.5%, and 6% in that order.
  • the lower limit of the Mg2 + content is preferably 0%, and more preferably 1%, 2%, 3%, and 4% in that order.
  • the Mg2+ content may be 0%.
  • the upper limit of the Mg 2+ content is preferably 40%, and more preferably 30%, 20%, 15%, 13%, 11%, 10%, 9%, 8%, 7%, 6.5%, and 6% in that order.
  • the lower limit of the Mg 2+ content is preferably 0%, and more preferably 1%, 2%, 3%, and 4% in that order.
  • the Mg 2+ content may be 0%.
  • the content of Mg 2+ is preferably within the above range.
  • the upper limit of the Ca2 + content is preferably 25%, and more preferably 20%, 15%, 10%, 9%, 8%, 7%, 6%, and 5% in that order.
  • the lower limit of the Ca2 + content is preferably 0%, and more preferably 0.5%, 1%, and 2% in that order.
  • the Ca2+ content may be 0%.
  • the upper limit of the Ca2 + content is preferably 25%, and more preferably 20%, 15%, 10%, 9%, 8%, 7%, 6%, and 5% in that order.
  • the lower limit of the Ca2 + content is preferably 0%, and more preferably 0.5%, 1%, and 2% in that order.
  • the Ca2+ content may be 0%.
  • the Ca2+ content is too high, the thermal stability of the glass may be impaired, and the glass transition temperature Tg and liquidus temperature TL may increase. From the viewpoint of obtaining an optical glass having the desired optical constants, it is preferable that the Ca2 + content be within the above range.
  • the upper limit of the Sr2 + content is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5%, in that order.
  • the lower limit of the Sr2 + content is preferably 0%.
  • the Sr2+ content may be 0%.
  • the upper limit of the Sr2 + content is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5% in that order.
  • the lower limit of the Sr2 + content is preferably 0%.
  • the Sr2+ content may be 0%.
  • Sr2 + is a component that increases the refractive index nd.
  • the content of Sr2 + is preferably within the above range.
  • the upper limit of the Ba2 + content is preferably 40%, and more preferably 30%, 25%, 20%, 18%, 16%, 15%, 14%, 13%, 12%, and 11% in that order.
  • the lower limit of the Ba2+ content is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, and 8% in that order.
  • the upper limit of the Ba2 + content is preferably 40%, and more preferably 30%, 25%, 20%, 18%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, and 6% in that order.
  • the lower limit of the Ba2+ content is preferably 0%, and more preferably 1%, 2%, 3%, and 4% in that order.
  • Ba2 + is a component that increases the refractive index nd, and at the same time, when contained in an appropriate amount, it lowers the liquidus temperature and increases the stability of the glass.
  • the content of Ba2 + is too high, the thermal stability and reheating stability of the glass may decrease.
  • the content of Ba2+ is too low, the thermal stability of the glass may decrease, and the volatilization of the glass components during melting may increase. Therefore, the content of Ba2 + is preferably within the above range.
  • the upper limit of the Zn2 + content is preferably 13%, more preferably 10%, 8%, 6%, and 5% in that order.
  • the lower limit of the Zn2 + content is preferably 0%, more preferably 0.5%, 1%, and 2% in that order.
  • the Zn2+ content may be 0%.
  • the upper limit of the Zn2 + content is preferably 13%, and more preferably 10%, 8%, 6%, and 5% in that order.
  • the lower limit of the Zn2 + content is preferably 0%, and more preferably 0.5%, 1%, and 2% in that order.
  • the Zn2+ content may be 0%.
  • Zn2 + is a glass component that acts to lower the glass transition temperature Tg. If the content of Zn2+ is too high, the specific gravity may increase, the thermal stability and chemical durability of the glass may decrease, and the Abbe number may increase, resulting in a failure to obtain the desired high refractive index characteristics. Therefore, from the viewpoint of obtaining an optical glass with an improved glass transition temperature Tg, it is preferable to set the content of Zn2 + within the above range.
  • the lower limit of the La3 + content is preferably 5%, and more preferably 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, and 17.5% in this order.
  • the upper limit of the La3 + content is preferably 50%, and more preferably 48%, 46%, 44%, 42%, 40%, 38%, 36%, 34%, 32%, 30%, 28%, 26%, 24%, 23%, 22%, 21.5%, 21%, 20.5%, and 20% in this order.
  • the lower limit of the La3 + content is preferably 5%, and more preferably 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, and 31% in that order.
  • the upper limit of the La3 + content is preferably 50%, and more preferably 49%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, 41%, 40%, 39%, 38%, 37%, 36%, 35%, and 34% in that order.
  • the content of La3 + is within the above range.
  • the upper limit of the Gd3 + content is preferably 50%, and more preferably 40%, 30%, 20%, 15%, 10%, 8%, 6%, 4%, 3%, 2%, and 1% in that order.
  • the lower limit of the Gd3 + content is preferably 0%.
  • the Gd3+ content may be 0%.
  • the upper limit of the Gd3 + content is preferably 50%, and more preferably 45%, 40%, 35%, 30%, 28%, 26%, 24%, 22%, 20%, 18%, 16%, and 15% in that order.
  • the lower limit of the Gd3 + content is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, and 12% in that order.
  • the volatilization of glass components can be suppressed and the refractive index nd can be increased.
  • the content of Gd 3+ becomes too high, the thermal stability of the glass decreases.
  • the content of Gd 3+ becomes too high, the specific gravity of the glass increases, which is not preferable.
  • the content of Gd 3+ is within the above range.
  • the upper limit of the Y3 + content is preferably 50%, and more preferably 48%, 46%, 44%, 42%, 40%, 38%, 36%, 34%, 32%, 30%, 28%, 26%, 25%, 24%, 23%, 22.5%, 22%, and 21.5% in this order.
  • the lower limit of the Y3 + content is preferably 0%, and more preferably 1%, 5%, 8%, 10%, 12%, 14%, 16%, and 18% in this order.
  • the Y3+ content may be 0%.
  • the upper limit of the content of Y3 + is preferably 50%, and more preferably 48%, 46%, 44%, 42%, 40%, 38%, 36%, 34%, 32%, 30%, 28%, 26%, 24%, 22%, 20%, 18%, 16%, 14%, 12%, 10%, 8%, 6%, 5%, 4%, 3%, and 2% in that order.
  • the lower limit of the content of Y3 + is preferably 0%, and more preferably 0.01%, 0.05%, 0.1%, 0.5%, and 1% in that order.
  • the content of Y3+ may be 0%.
  • the content of Y3+ is within the above range.
  • the upper limit of the Yb 3+ content is preferably 50%, and more preferably 40%, 30%, 20%, 15%, 10%, 8%, 6%, 4%, 3%, 2%, and 1%, in that order.
  • the lower limit of the Yb 3+ content is preferably 0%.
  • the Yb 3+ content may be 0%.
  • the upper limit of the Yb3 + content is preferably 50%, and more preferably 40%, 30%, 20%, 15%, 10%, 8%, 6%, 4%, 3%, 2%, and 1% in that order.
  • the lower limit of the Yb3 + content is preferably 0%.
  • the Yb3+ content may be 0%.
  • Yb3 + has a larger molecular weight than La3 + , Gd3 + , and Y3 + , and therefore increases the specific gravity of the glass. If the content of Yb3 + is too high, the thermal stability of the glass decreases. From the viewpoint of preventing the decrease in the thermal stability of the glass and suppressing the increase in the specific gravity, the content of Yb3 + is preferably within the above range.
  • the upper limit of the Ti4 + content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order.
  • the lower limit of the Ti4 + content is preferably 0%, and may be 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, or 1.6%.
  • the Ti4+ content may be 0%.
  • the upper limit of the Ti4 + content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5%, in that order.
  • the lower limit of the Ti4 + content is preferably 0%, and may be 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, or 1.6%.
  • the content of Ti 4+ be within the above range.
  • the upper limit of the Nb5 + content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order.
  • the lower limit of the Nb5 + content is preferably 0%, and more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6% in that order.
  • the Nb5+ content may be 0%.
  • the upper limit of the Nb5 + content is preferably 20%, more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order.
  • the lower limit of the Nb5 + content is preferably 0%, more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6% in that order.
  • the content of Nb 5+ be within the above range.
  • the upper limit of the W6 + content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order.
  • the lower limit of the W6+ content is preferably 0%, and more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6% in that order.
  • the W6+ content may be 0%.
  • the upper limit of the W6+ content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order.
  • the lower limit of the W6+ content is preferably 0%, and more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6% in that order.
  • the content of W 6+ be in the above range.
  • the upper limit of the Bi3 + content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order.
  • the lower limit of the Bi3 + content is preferably 0%, and may be 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, or 1.6%.
  • the Bi3+ content may be 0%.
  • the upper limit of the Bi3 + content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order.
  • the lower limit of the Bi3 + content is preferably 0%, and may be 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, or 1.6%.
  • the Bi3+ content may be 0%.
  • the content of Bi3 + be in the above range.
  • the upper limit of the Zr4 + content is preferably 10%, and more preferably 8%, 6%, 4%, 3%, 2%, and 1% in that order.
  • the lower limit of the Zr4 + content is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5% in that order.
  • the Zr4+ content may be 0%.
  • the upper limit of the Zr4 + content is preferably 10%, and more preferably 9%, 8%, 7%, 6%, 5%, and 4% in that order.
  • the lower limit of the Zr4 + content is preferably 0%, and more preferably 0.05%, 0.1%, 0.5%, 1.0%, 1.5%, and 2.0% in that order.
  • the Zr4+ content may be 0%.
  • the upper limit of the Ta5 + content is preferably 10%, and more preferably 8%, 6%, 4%, 3%, 2%, and 1% in that order.
  • the lower limit of the Ta5 + content is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5% in that order.
  • the Ta5+ content may be 0%.
  • the upper limit of the Ta5 + content is preferably 10%, and more preferably 8%, 6%, 4%, 3%, 2%, and 1% in that order.
  • the lower limit of the Ta5 + content is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5% in that order.
  • the Ta5+ content may be 0%.
  • Ta5 + is a component that contributes to high refraction and low dispersion of glass.
  • the content of Ta5 + is too high, the raw material cost may increase, and the meltability of the glass may decrease. Furthermore, the specific gravity may increase. Therefore, the content of Ta5 + is preferably within the above range.
  • the upper limit of the Ge4 + content is preferably 5%, and more preferably 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, and 0.5% in that order.
  • the lower limit of the Ge4 + content is preferably 0%.
  • the Ge4+ content may be 0%.
  • the upper limit of the Ge4 + content is preferably 5%, and more preferably 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, and 0.5% in that order.
  • the lower limit of the Ge4 + content is preferably 0%.
  • the Ge4+ content may be 0%.
  • Ge 4+ has the function of increasing the high dispersibility of the glass, but is an extremely expensive component among commonly used glass components, and therefore, from the viewpoint of reducing the production cost of the glass, it is preferable that the content of Ge 4+ is within the above range.
  • the content of Sc 3+ is preferably 2% or less.
  • the lower limit of the content of Sc 3+ is preferably 0%.
  • the content of Hf 4+ is preferably 2% or less.
  • the lower limit of the content of Hf 4+ is preferably 0%.
  • Sc 3+ and Hf 4+ have the effect of increasing the dispersibility of the glass, but are expensive components, so the contents of Sc 3+ and Hf 4+ are preferably within the above ranges.
  • the content of Lu 3+ is preferably 2% or less.
  • the lower limit of the content of Lu 3+ is preferably 0%.
  • Lu 3+ has the function of increasing the dispersibility of the glass, but because of its large molecular weight, it is also a glass component that increases the specific gravity of the glass, so the content of Lu 3+ is preferably within the above range.
  • the glass according to this embodiment is preferably composed of Si4 + and B3 + as essential components, and Ca2 + , Zn2 + , P5 + , Al3 + , Li + , Na + , K + , Rb + , Cs + , Mg2+ , Sr2+ , Ba2+, La3 + , Gd3 + , Y3 + , Ti4 + , Nb5+ , W6 + , Bi3 + , Ta5 + , and Zr4 + as optional components.
  • the total content of these glass components is preferably 95% or more, more preferably 98% or more, even more preferably 99% or more, and particularly preferably 99.5% or more.
  • the optical glass according to this embodiment contains O2- as an anion component.
  • the upper limit of the O2- content is preferably 90 anion%, and more preferably 80 anion%, 75 anion%, 73 anion%, 71 anion%, 69 anion%, 67 anion%, 65 anion%, 63 anion%, 61 anion%, 60 anion%, 59 anion%, 58 anion%, 57 anion%, 56 anion%, and 55 anion%, in that order.
  • the lower limit of the O2- content is preferably 10 anion%, and more preferably 15 anion%, 20 anion%, 25 anion%, 30 anion%, 30 anion%, 32 anion%, 34 anion%, 36 anion%, 38 anion%, 40 anion%, 42 anion%, 44 anion%, 45 anion%, 46 anion%, 47 anion%, 48 anion%, 49 anion%, 50 anion%, and 51 anion%, in that order.
  • the upper limit of the content of O 2- is preferably 90 anion%, more preferably 88 anion%, 86 anion%, 84 anion%, 82 anion%, 80 anion%, 78 anion%, 76 anion%, 75 anion%, 74 anion%, 73 anion%, 72 anion%, 71 anion%, 70 anion%, 69 anion%, and 68 anion%, in that order.
  • the lower limit of the content of O 2- is preferably 10 anion%, more preferably 15 anion%, 20 anion%, 25 anion%, 30 anion%, 35 anion%, 40 anion%, 45 anion%, 50 anion%, 55 anion%, 60 anion%, 61 anion%, 62 anion%, 63 anion%, 64 anion%, and 65 anion%, in that order.
  • the optical glass according to this embodiment may contain a component other than O 2- and F - as an anion component.
  • an anion component other than O 2- and F - include Cl - , Br - , and I - .
  • Cl - , Br - , and I - are all likely to volatilize during melting of the glass. The volatilization of these components causes problems such as fluctuations in glass properties, reduction in glass homogeneity, and significant wear of melting equipment. Therefore, the content of Cl - is preferably less than 5 anion%, more preferably less than 3 anion%, even more preferably less than 1 anion%, particularly preferably less than 0.5 anion%, and even more preferably less than 0.25 anion%.
  • the total content of Br - and I - is preferably less than 5 anion%, more preferably less than 3 anion%, even more preferably less than 1 anion%, particularly preferably less than 0.5 anion%, even more preferably less than 0.1 anion%, and even more preferably 0 anion%.
  • the glass according to this embodiment is preferably composed essentially of the above glass components, but may contain other components as long as they do not impede the effects of the present invention. Furthermore, the present invention does not exclude the inclusion of unavoidable impurities.
  • Sb ions can be added from the viewpoint of suppressing a decrease in transmittance at wavelengths of around 360 nm and around 375 nm.
  • the upper limit of the content of Sb ions is preferably 1.0000 mass% in terms of external percentage, and more preferably 0.5000 mass%, 0.1000 mass%, 0.0900 mass%, 0.0800 mass%, 0.0700 mass%, 0.0600 mass%, 0.0500 mass%, 0.0400 mass%, 0.0300 mass%, 0.0250 mass%, 0.0200 mass%, 0.0150 mass%, 0.0100 mass%, 0.0090 mass%, 0.0080 mass%, 0.0070 mass%, 0.0060 mass%, and 0.0050 mass% in that order.
  • the content of Sb ions is preferably 1.0 mass ppm or more in terms of the external percentage. Note that 1.0 mass ppm is 0.0001 mass%.
  • the lower limit of the content of Sb ions is more preferably 0.0005 mass% in terms of the external percentage, and further more preferably 0.0008 mass%, 0.0010 mass%, 0.0012 mass%, 0.0014 mass%, 0.0016 mass%, 0.0018 mass%, 0.0020 mass%, 0.0022 mass%, 0.0024 mass%, 0.0026 mass%, 0.0028 mass%, 0.0030 mass%, 0.0032 mass%, 0.0034 mass%, 0.0036 mass%, and 0.0038 mass% in that order.
  • Sb ions can be added to glass, for example, by Sb 2 O 3 or Sb 2 S 3.
  • Sb ions include all Sb ions having trivalent, pentavalent, and other valences.
  • the content of Sb ions is an external percentage. That is, the content of Sb ions is expressed in mass% when the total content of all glass components other than Sb ions is 100 mass%. From the viewpoint of suppressing the decrease in transmittance at wavelengths of around 360 nm and 375 nm, it is preferable to set the content of Sb ions to the above range.
  • the optical glass also provides high transmittance over a wide range of the visible light region.
  • the glass does not contain any coloring elements.
  • coloring elements include Cu, Co, Ni, Fe, Cr, Eu, Nd, Er, and V.
  • Each element is preferably contained at less than 100 ppm by mass, more preferably 0 to 80 ppm by mass, and even more preferably 0 to 50 ppm by mass, and it is particularly preferable that the glass is substantially free of these elements.
  • Ga, Te, Tb, etc. are components that do not need to be incorporated and are expensive components. Therefore, the range of the content of Ga 2 O 3 , TeO 2 , and TbO 2 expressed in mass % is preferably 0 to 0.1%, more preferably 0 to 0.05%, even more preferably 0 to 0.01%, still more preferably 0 to 0.005%, even more preferably 0 to 0.001%, and it is particularly preferable that they are not substantially contained.
  • the refractive index nd is preferably 1.58 to 1.78, and can be 1.59 to 1.75, 1.60 to 1.72, 1.61 to 1.69, 1.62 to 1.68, 1.63 to 1.67, 1.64 to 1.66, or 1.67 to 1.69.
  • the refractive index nd is preferably 1.60 to 1.92, and can be 1.65 to 1.87, 1.70 to 1.82, 1.75 to 1.80, 1.76 to 1.79, or 1.65 to 1.68.
  • the refractive index nd can be adjusted to a desired value by appropriately adjusting the content of each glass component.
  • Components that act to relatively increase the refractive index nd include Nb5 + , Ti4 + , W6 + , Bi3 + , Zr4 + , Ta5 + , La3 + , Gd3 + , Y3 + , etc.
  • components that act to relatively decrease the refractive index nd include Si4 + , B3+ , Li + , Na + , K + , etc.
  • the lower limit of the partial dispersion ratio Pg,F in the visible short wavelength region is preferably 0.5200, and more preferably 0.5250, 0.5300, 0.5350, 0.5400, 0.5410, 0.5420, 0.5430, 0.5440, and 0.5450, in that order.
  • the lower limit of the partial dispersion ratio Pg,F in the visible short wavelength region is preferably 0.5200, and more preferably 0.5250, 0.5300, 0.5350, 0.5400, 0.5450, 0.5500, 0.5510, 0.5520, 0.5530, 0.5540, and 0.5550, in that order.
  • the upper limit of the partial dispersion ratio Pg,F is not particularly limited, but is usually 0.5700, and preferably 0.5650.
  • the partial dispersion ratio Pg,F preferably satisfies the following formula [3-1]. Pg,F ⁇ 0.6200-0.0014 ⁇ d...[3-1] It is more preferable that the partial dispersion ratio Pg,F satisfies the following formula [3-2], and more preferably satisfies the following formula [3-3], the following formula [3-4], the following formula [3-5], and the following formula [3-6] in that order.
  • the partial dispersion ratio Pg,F satisfies the following formula [4-1].
  • the partial dispersion ratio Pg,F satisfies the following formula [4-2], and more preferably satisfies the following formula [4-3], the following formula [4-4], the following formula [4-5], and the following formula [4-6] in that order.
  • the partial dispersion ratio Pg,F satisfy the above formula.
  • the specific gravity of the optical glass according to this embodiment is preferably 6.0 or less, more preferably 5.5 or less, 5.0 or less, 4.8 or less, and 4.6 or less in that order. Furthermore, in the case of optical glasses with higher refractive index and higher dispersion, the specific gravity is preferably 6.0 or less, more preferably 5.9 or less, 5.8 or less, 5.7 or less, 5.6 or less, and 5.5 or less in that order.
  • Components that relatively increase the specific gravity are Ba2 + , La3 + , Zr4+ , Nb5+ , Ta5 + , etc.
  • components that relatively decrease the specific gravity are Si4 + , B3 + , Li + , Na + , Mg2+ , etc.
  • the specific gravity can be controlled by appropriately adjusting the contents of these components.
  • the upper limit of the liquidus temperature LT of the optical glass according to this embodiment is preferably 1200° C., and more preferably 1150° C., 1100° C., 1050° C., 1000° C., 980° C., 970° C., 960° C., 950° C., 940° C., 930° C., 920° C., 910° C., 900° C., and 890° C.
  • the upper limit of the liquidus temperature LT is preferably 1200° C., and more preferably 1190° C., 1180° C., 1170° C., 1160° C., 1150° C., 1140° C., 1130° C., and 1120° C., in that order.
  • the lower limit of the liquidus temperature LT is not particularly limited.
  • the liquidus temperature LT is determined by the balance of the contents of all the glass components. Among them, the contents of Si4 + , B3 + , Li + , Na + , K + , etc. have a large effect on the liquidus temperature LT. Furthermore, if the contents of Zr4 + , Al3 + , etc. are high, the liquidus temperature rises.
  • the liquidus temperature is determined as follows: 10 cc (10 ml) of glass is placed in a platinum crucible and melted at a temperature of 1200°C or higher for 15 to 30 minutes, then cooled to below the glass transition temperature Tg. The glass together with the platinum crucible is placed in a melting furnace at the specified temperature and held there for 2 hours. The holding temperature is set at any temperature in 10°C increments, and after holding for 2 hours, it is cooled and the presence or absence of crystals inside the glass is observed with a 100x optical microscope. This process is repeated for each temperature, and the lowest temperature at which no crystals precipitate is taken as the liquidus temperature.
  • the light transmittance of the optical glass according to this embodiment can be evaluated by the coloring degrees ⁇ 80, ⁇ 70, and ⁇ 5.
  • the spectral transmittance of a glass sample having a thickness of 10.0 mm ⁇ 0.1 mm is measured in the wavelength range of 200 to 700 nm.
  • the wavelength at which the external transmittance is 80% is defined as ⁇ 80
  • the wavelength at which the external transmittance is 70% is defined as ⁇ 70
  • the wavelength at which the external transmittance is 5% is defined as ⁇ 5.
  • the ⁇ 80 of the optical glass according to this embodiment is preferably 450 nm or less, more preferably 400 nm or less, and even more preferably 350 nm or less.
  • ⁇ 70 is preferably 430 nm or less, more preferably 380 nm or less, and even more preferably 330 nm or less.
  • ⁇ 5 is preferably 380 nm or less, more preferably 330 nm or less, and even more preferably 280 nm or less.
  • ⁇ 80 is preferably 450 nm or less, more preferably 400 nm or less, and even more preferably 380 nm or less.
  • ⁇ 70 is preferably 430 nm or less, more preferably 380 nm or less, and even more preferably 360 nm or less.
  • ⁇ 5 is preferably 380 nm or less, more preferably 330 nm or less, and even more preferably 320 nm or less.
  • the acid resistance Da is preferably class 5 or higher, more preferably class 4 or higher, and further preferably class 3 or higher.
  • the acid resistance Da is evaluated by placing a powdered glass (particle size 425 to 600 ⁇ m) of a mass equivalent to the specific gravity in a platinum cage, immersing it in a quartz glass round-bottom flask containing 80 mL of 0.01 mol/L nitric acid aqueous solution for 60 minutes, and classifying and evaluating the grade in Table B according to the weight loss rate (%).
  • the water resistance Dw is preferably class 5 or higher, more preferably class 4 or higher, and further preferably class 3 or higher.
  • the upper limit of the difference ( ⁇ T360) between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 360 nm is preferably 31.0%, and more preferably 30.0%, 28.0%, 26.0%, 24.0%, 22.0%, 20.0%, 18.0%, 16.0%, 15.0%, 14.0%, 13.0%, 12.0%, 11.0%, 10.0%, 9.0%, 8.0%, 7.0%, and 6.0% in that order.
  • the lower limit of ⁇ T360 is not particularly limited, but is generally 2 to 30%. ⁇ T360 can be adjusted by introducing Sb ions.
  • ⁇ T360 may increase.
  • the upper limit of the difference ( ⁇ T375) between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 375 nm is preferably 15.0%, and more preferably 13.0%, 11.0%, 10.0%, 9.0%, 8.0%, 7.5%, 7.0%, 6.8%, 6.7%, 6.6%, 6.5%, 6.4%, 6.3%, 6.2%, 6.1%, and 6.0% in that order.
  • the lower limit of ⁇ T375 is not particularly limited, but is generally 2 to 15%. ⁇ T375 can be adjusted by introducing Sb ions.
  • ⁇ T375 can increase.
  • ⁇ T375 in the above range, a decrease in the transmittance at a wavelength in the vicinity of 375 nm can be suppressed.
  • External transmittance is defined as the percentage of transmitted light intensity relative to incident light intensity when light is incident in the thickness direction of a glass sample [transmitted light intensity/incident light intensity x 100]. Note that external transmittance also includes the reflection loss of light rays on the sample surface.
  • the glass according to the present embodiment may be produced by blending glass raw materials to obtain the above-mentioned predetermined composition, and using the blended glass raw materials in accordance with a known glass manufacturing method.
  • a plurality of compounds may be blended and thoroughly mixed to obtain a batch raw material, and the batch raw material may be placed in a platinum crucible or the like to be roughly melted (rough melt).
  • the molten material obtained by the rough melting is quenched and crushed to produce cullet.
  • the cullet is then placed in a platinum crucible, heated, and remelted (remelt) to obtain a molten glass, which is then clarified and homogenized, molded, and slowly cooled to obtain an optical glass.
  • a known method may be applied to the molding and slow cooling of the molten glass.
  • the desired glass components can be introduced into the glass in the desired content
  • the compounds used when mixing the batch raw materials include oxides, carbonates, nitrates, hydroxides, fluorides, composite oxides, fluorosilicates, and fluoroborates.
  • Press molding of glass material for press molding can be carried out by pressing the glass material for press molding in a heated and softened state into a press mold. Both heating and press molding can be carried out in the atmosphere. If a powdered mold release agent such as boron nitride is evenly applied to the surface of the glass material for press molding, and then it is heated and press molded, it is possible to reliably prevent the glass from fusing with the mold and also to smoothly stretch the glass along the molding surface of the mold. A homogeneous optical element blank can be obtained by annealing the glass after press molding to reduce distortion inside the glass.
  • glass materials for press molding include precision press molding preforms and glass materials for press molding optical element blanks (glass gobs for press molding), and include glass chunks with a mass equivalent to the mass of the desired press molded product.
  • Glass materials for press molding are also called preforms, and in addition to those that are used for press molding as is, they also include those that are used for press molding after undergoing mechanical processing such as cutting, grinding, and polishing.
  • Cutting methods include forming a groove in the area of the surface of the glass plate to be cut by a method called scribing, and then applying local pressure to the grooved area from the back side of the surface where the groove was formed, thereby breaking the glass plate at the grooved area, and cutting the glass plate with a cutting blade.
  • Grinding methods include spherical processing and smoothing processing using a curve generator.
  • Polishing methods include polishing with abrasive grains such as cerium oxide and zirconium oxide.
  • the glass material for press molding according to this embodiment is made of optical glass with excellent mechanical properties, and is therefore less susceptible to damage during handling and processing.
  • a problem with glass materials for precision press molding was that scratches on the surface of the glass material tended to remain on the surface of optical elements after press molding, particularly on the optically functional surface.
  • the glass material for press molding according to this embodiment has excellent mechanical properties and is less susceptible to scratches on the glass material surface, and is therefore preferably used as a glass material for precision press molding. Furthermore, even when mechanical processing, i.e. grinding and polishing, is performed on the press-molded product after press molding to produce an optical element, a press-molded product that is less susceptible to damage by mechanical processing can be produced.
  • an optical element blank made of the optical glass according to this embodiment can be provided.
  • the optical element blank is a glass molded body having a shape similar to that of the optical element to be manufactured.
  • the optical element blank can be produced by a method of molding glass into a shape that includes a processing allowance to be removed when processing into the shape of the optical element to be manufactured, or the like.
  • the optical element blank can be produced by a method of heating and softening a glass material for press molding and press molding it (reheat press method), a method of supplying a molten glass lump to a press mold by a known method and press molding it (direct press method), or the like.
  • optical element blank described above may be used.
  • molten glass is poured into a mold and molded into a plate shape to manufacture a glass material made of the optical glass according to the present invention.
  • the obtained glass material is appropriately cut, ground, and polished to prepare cut pieces having a size and shape suitable for press molding.
  • the cut pieces are heated and softened, and press molded (reheat pressed) by a known method to prepare an optical element blank that is similar to the shape of the optical element.
  • the optical element can be manufactured by a method including a process of processing the optical element blank. Examples of the processing include cutting, cutting, rough grinding, fine grinding, and polishing. When performing such processing, the use of the above glass can reduce breakage, and high-quality optical elements can be stably supplied.
  • optical elements include spherical lenses, aspherical lenses, prisms, diffraction gratings, etc.
  • Lens shapes include biconvex lenses, plano-convex lenses, biconcave lenses, plano-concave lenses, convex meniscus lenses, concave meniscus lenses, etc.
  • the optically functional surfaces of optical elements may be coated with an anti-reflection film, a total reflection film, etc., depending on the intended use.
  • the optical element according to this embodiment is made of optical glass with excellent mechanical properties, so it is less likely to be damaged during handling and processing. In particular, it is less likely to be damaged when the optical element is fixed. For example, during the centering process of a lens, the lens surface is less likely to be damaged even when it is clamped and fixed from both sides.
  • Example 1 Glass samples having the glass compositions shown in Table 1(1) to (8), Table 2(1) to (8), Table 3(1) to (9), Table 4(1) to (8), Table 5(1) to (8), Table 6(1) to (8), Table 7(1) to (8), Table 8(1) to (8), and Table 9(1) to (8) were prepared by the following procedure, and various evaluations were performed.
  • the content of glass components not shown is 0.00 cationic %.
  • the contents of Rb + , Cs + , and Ge 4+ were each 0.00 cationic %.
  • the ratio of the number of anions to the number of cations is the molar ratio of the total number of cations to the total number of anions, and can be calculated from the composition. Specifically, the sum of the positive charges of each cation when the total number of cations is 100 (an arbitrary constant) is calculated, and the total number of anions when the total number of cations is 100 is calculated by combining the negative charges of the anions that are the same number as the total number of cations and the anion molar percentage. From this calculated value, the ratio of the number of anions to the number of cations (anion number/cation number) was calculated.
  • the obtained glass sample was further annealed at about the glass transition temperature Tg for about 30 minutes to about 2 hours, and then cooled to room temperature in a furnace at a temperature drop rate of -30°C/hour to obtain an annealed sample.
  • the refractive index, Abbe number ⁇ d, partial dispersion ratio Pg,F, ⁇ Pg,F, specific gravity, glass transition temperature Tg, liquidus temperature LT, ⁇ 80, ⁇ 70, ⁇ 5, ⁇ T360, and ⁇ T375 of the obtained annealed sample were measured. The results are shown in Tables 2 (1) to (8).
  • n2 a0 + a1 ⁇ 2 + a2 ⁇ -2 + a3 ⁇ -4 + a4 ⁇ -6 + a5 ⁇ -8
  • n is the refractive index
  • ⁇ is the wavelength ( ⁇ m)
  • a 0 , a 1 , a 2 , a 3 , a 4 , and a 5 are constants.
  • the refraction nd is the refractive index at a wavelength of 587.56 nm.
  • the Abbe number ⁇ d is expressed as follows using the refractive indices nd, nF, and nC at the d line, F line, and C line, respectively.
  • ⁇ d (nd-1)/(nF-nC)
  • Glass transition temperature Tg was measured using a differential scanning calorimeter (DSC3300SA) manufactured by NETZSCH JAPAN at a heating rate of 10° C./min.
  • the annealed sample was processed to have a thickness of 10 mm and parallel, optically polished flat surfaces, and the spectral transmittance was measured in the wavelength range from 280 nm to 700 nm.
  • the intensity of the light beam incident on the flat surface was defined as intensity A
  • the intensity of the light beam emerging from the other flat surface was defined as intensity B
  • the spectral transmittance B/A was calculated.
  • the wavelength at which the spectral transmittance is 70% is defined as ⁇ 70
  • the wavelength at which the spectral transmittance is 5% is defined as ⁇ 5.
  • the spectral transmittance includes the reflection loss of the light beam on the sample surface.
  • the above annealed sample was processed to have a thickness of 10.0 mm ⁇ 0.1 mm and parallel, optically polished flat surfaces, and the external transmittance was measured at wavelengths of 700 nm and 375 nm.
  • the difference between the external transmittance at a wavelength of 700 nm (T700) and the external transmittance at a wavelength of 375 nm (T375) was calculated and designated as ⁇ T375.
  • External transmittance is defined as the percentage of transmitted light intensity relative to incident light intensity when light is incident in the thickness direction of a glass sample [transmitted light intensity/incident light intensity x 100]. Note that external transmittance also includes the reflection loss of light rays on the sample surface.
  • Example 2 Using each of the optical glasses produced in Example 1, lens blanks were produced by a known method, and the lens blanks were processed by a known method such as polishing to produce various lenses.
  • the optical lenses produced include various lenses such as a biconvex lens, a biconcave lens, a plano-convex lens, a plano-concave lens, a concave meniscus lens, and a convex meniscus lens.
  • an optical glass according to one aspect of the present invention can be produced. Furthermore, it is of course possible to arbitrarily combine two or more of the items described in the specification as examples or preferred ranges.

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